Update code block in readme for rbenv-doctor script (#1353)

Co-authored-by: Mislav Marohnić <git@mislav.net>

README.md

@@ -127,9 +127,9 @@ Version names to rbenv are simply the names of the directories in
 If you're on macOS, we recommend installing rbenv with
 [Homebrew](https://brew.sh).
 
-    ~~~ sh
+    ```sh
-    $ brew install rbenv
+    brew install rbenv
-    ~~~
+    ```
     
    Note that this also installs `ruby-build`, so you'll be ready to
    install other Ruby versions out of the box.
@@ -139,13 +139,14 @@ If you're on macOS, we recommend installing rbenv with
     To upgrade to the latest rbenv and update ruby-build with newly released
     Ruby versions, upgrade the Homebrew packages:
 
-    ~~~ sh
+    ```sh
-    $ brew upgrade rbenv ruby-build
+    brew upgrade rbenv ruby-build
-    ~~~
+    ```
 - **Debian, Ubuntu and their derivatives**
-    ~~~ sh
+    
-    $ sudo apt install rbenv
+    ```sh
-    ~~~
+    sudo apt install rbenv
+    ```
 - **Arch Linux and it's derivatives**
 
   Archlinux has an [AUR Package](https://aur.archlinux.org/packages/rbenv/) for
@@ -154,9 +155,9 @@ If you're on macOS, we recommend installing rbenv with
 
 2. Set up rbenv in your shell.
 
-    ~~~ sh
+    ```sh
-    $ rbenv init
+    rbenv init
-    ~~~
+    ```
 
    Follow the printed instructions to [set up rbenv shell integration](#how-rbenv-hooks-into-your-shell).
 
@@ -166,8 +167,11 @@ If you're on macOS, we recommend installing rbenv with
 4. Verify that rbenv is properly set up using this
    [rbenv-doctor](https://github.com/rbenv/rbenv-installer/blob/main/bin/rbenv-doctor) script:
 
-    ~~~ sh
+    ```sh
-    $ curl -fsSL https://github.com/rbenv/rbenv-installer/raw/main/bin/rbenv-doctor | bash
+    curl -fsSL https://github.com/rbenv/rbenv-installer/raw/main/bin/rbenv-doctor | bash
+    ```
+
+    ```sh
     Checking for `rbenv' in PATH: /usr/local/bin/rbenv
     Checking for rbenv shims in PATH: OK
     Checking `rbenv install' support: /usr/local/bin/rbenv-install (ruby-build 20170523)
@@ -176,7 +180,7 @@ If you're on macOS, we recommend installing rbenv with
       You can install Ruby versions like so: rbenv install 2.2.4
     Checking RubyGems settings: OK
     Auditing installed plugins: OK
-    ~~~
+    ```
 
 5. That's it! Installing rbenv includes ruby-build, so now you're ready to
    [install some other Ruby versions](#installing-ruby-versions) using
@@ -194,16 +198,16 @@ a systemwide install.
 
 1. Clone rbenv into `~/.rbenv`.
 
-    ~~~ sh
+    ```sh
-    $ git clone https://github.com/rbenv/rbenv.git ~/.rbenv
+    git clone https://github.com/rbenv/rbenv.git ~/.rbenv
-    ~~~
+    ```
 
     Optionally, try to compile dynamic bash extension to speed up rbenv. Don't
     worry if it fails; rbenv will still work normally:
 
-    ~~~
+    ```sh
-    $ cd ~/.rbenv && src/configure && make -C src
+    cd ~/.rbenv && src/configure && make -C src
-    ~~~
+    ```
 
 2. Add `~/.rbenv/bin` to your `$PATH` for access to the `rbenv`
    command-line utility.
@@ -211,30 +215,30 @@ a systemwide install.
    * For **bash**:
      
      Ubuntu Desktop users should configure `~/.bashrc`:
-     ~~~ bash
+     ```bash
-     $ echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bashrc
+     echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bashrc
-     ~~~
+     ```
 
      On other platforms, bash is usually configured via `~/.bash_profile`:
-     ~~~ bash
+     ```bash
-     $ echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bash_profile
+     echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bash_profile
-     ~~~
+     ```
      
    * For **Zsh**:
-     ~~~ zsh
+     ```zsh
-     $ echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.zshrc
+     echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.zshrc
-     ~~~
+     ```
    
    * For **Fish shell**:
-     ~~~ fish
+     ```fish
-     $ set -Ux fish_user_paths $HOME/.rbenv/bin $fish_user_paths
+     set -Ux fish_user_paths $HOME/.rbenv/bin $fish_user_paths
-     ~~~
+     ```
 
 3. Set up rbenv in your shell.
 
-   ~~~ sh
+   ```sh
-   $ ~/.rbenv/bin/rbenv init
+   ~/.rbenv/bin/rbenv init
-   ~~~
+   ```
    
    Follow the printed instructions to [set up rbenv shell integration](#how-rbenv-hooks-into-your-shell).
 
@@ -244,8 +248,11 @@ a systemwide install.
 5. Verify that rbenv is properly set up using this
    [rbenv-doctor](https://github.com/rbenv/rbenv-installer/blob/main/bin/rbenv-doctor) script:
 
-    ~~~ sh
+    ```sh
-    $ curl -fsSL https://github.com/rbenv/rbenv-installer/raw/main/bin/rbenv-doctor | bash
+    curl -fsSL https://github.com/rbenv/rbenv-installer/raw/main/bin/rbenv-doctor | bash
+    ```
+
+    ```sh
     Checking for `rbenv' in PATH: /usr/local/bin/rbenv
     Checking for rbenv shims in PATH: OK
     Checking `rbenv install' support: /usr/local/bin/rbenv-install (ruby-build 20170523)
@@ -254,7 +261,7 @@ a systemwide install.
       You can install Ruby versions like so: rbenv install 2.2.4
     Checking RubyGems settings: OK
     Auditing installed plugins: OK
-    ~~~
+    ```
 
 6. _(Optional)_ Install [ruby-build][], which provides the
    `rbenv install` command that simplifies the process of
@@ -265,18 +272,18 @@ a systemwide install.
 If you've installed rbenv manually using Git, you can upgrade to the
 latest version by pulling from GitHub:
 
-~~~ sh
+```sh
-$ cd ~/.rbenv
+cd ~/.rbenv
-$ git pull
+git pull
-~~~
+```
 
 #### Updating the list of available Ruby versions
 
 If you're using the `rbenv install` command, then the list of available Ruby versions is not automatically updated when pulling from the rbenv repo. To do this manually:
 
 ```sh
-$ cd ~/.rbenv/plugins/ruby-build
+cd ~/.rbenv/plugins/ruby-build
-$ git pull
+git pull
 ```
 
 ### How rbenv hooks into your shell
@@ -318,7 +325,7 @@ is provided by the [ruby-build][] project. If you installed it either
 as part of GitHub checkout process outlined above or via Homebrew, you
 should be able to:
 
-~~~ sh
+```sh
 # list latest stable versions:
 $ rbenv install -l
 
@@ -327,7 +334,7 @@ $ rbenv install -L
 
 # install a Ruby version:
 $ rbenv install 2.0.0-p247
-~~~
+```
 
 Set a Ruby version to finish installation and start using commands `rbenv global 2.0.0-p247` or `rbenv local 2.0.0-p247`
 
@@ -383,7 +390,7 @@ uninstall from the system.
   remove rbenv shims directory from PATH, and future invocations like
   `ruby` will execute the system Ruby version, as before rbenv.
 
-  `rbenv` will still be accessible on the command line, but your Ruby
+   While disabled, `rbenv` will still be accessible on the command line, but your Ruby
   apps won't be affected by version switching.
 
 2. To completely **uninstall** rbenv, perform step (1) and then remove
@@ -393,17 +400,11 @@ uninstall from the system.
         rm -rf `rbenv root`
 
    If you've installed rbenv using a package manager, as a final step
-   perform the rbenv package removal.
+   perform the rbenv package removal:
-   - Homebrew:
+   - Homebrew: `brew uninstall rbenv`
-   
+   - Debian, Ubuntu, and their derivatives: `sudo apt purge rbenv`
-        `brew uninstall rbenv`
+   - Archlinux and its derivatives: `sudo pacman -R rbenv`
-   - Debian, Ubuntu and their derivatives:
+
-        
-        `sudo apt purge rbenv`
-  
-   - Archlinux and it's derivatives:
-  
-          `sudo pacman -R rbenv`
 
 ## Command Reference