Add 202009 bugathon event based on the one just concluded.

While here, fix a grammar nit.

Approved by:	bcr
Differential Revision:	https://reviews.freebsd.org/D25642

share/xml/events2020.xml

@@ -211,7 +211,7 @@
       <city>Online</city>
       <site>live.FreeBSD.org</site>
     </location>
-    <description>On the July 11th 2020 from 1400-2100 UTC we will be
+    <description>On July 11th 2020 from 1400-2100 UTC we will be
       running a coordinated virtual Bug Squash. FreeBSD has a Problem
       Report (PR) database where users and developers are encouraged
       to file issues and regressions they find in both the base system
@@ -222,4 +222,34 @@
       invited to attend and participate via the live video stream and
       IRC channel.</description>
   </event>
+
+  <event id="bugsquash-2020-09-19">
+    <name>FreeBSD Bug Squash</name>
+    <url>https://wiki.freebsd.org/Bugathons</url>
+    <startdate>
+      <year>2020</year>
+      <month>09</month>
+      <day>19</day>
+    </startdate>
+    <enddate>
+      <year>2020</year>
+      <month>09</month>
+      <day>19</day>
+    </enddate>
+    <location>
+      <country code="CA">Canada</country>
+      <city>Online</city>
+      <site>live.FreeBSD.org</site>
+    </location>
+    <description>On September 19th 2020 from 1400-2100 UTC we will be
+      running a coordinated virtual Bug Squash. FreeBSD has a Problem
+      Report (PR) database where users and developers are encouraged
+      to file issues and regressions they find in both the base system
+      and ports tree. A Bug Squash is a focused session where we try to
+      triage, process, fix and close as many reports as we can from the
+      PR database. This September 11th Bug Squash we will focus on closing
+      as many PRs with patches as we can. Both users and developers are
+      invited to attend and participate via the live video stream and
+      IRC channel.</description>
+  </event>
 </events>