Add more options="header" to tables

Approved by:	carlavilla (implicitly)

website/content/en/where.adoc

@@ -132,7 +132,7 @@ If you are interested in a purely experimental *snapshot* release of FreeBSD-CUR
 
 [.tblbasic]
 [.tblDownload]
-[width="100%",cols="25%,25%,25%,25%",]
+[width="100%",cols="25%,25%,25%,25%",options="header",]
 |===
 |Installer Images |Virtual Machine Images |SD Card Images |Documentation
 a|
@@ -176,7 +176,7 @@ a|
 
 [.tblbasic]
 [.tblDownload]
-[width="100%",cols="25%,25%,25%,25%",]
+[width="100%",cols="25%,25%,25%,25%",options="header",]
 |===
 |Installer Images |Virtual Machine Images |SD Card Images |Documentation
 a|
@@ -219,7 +219,7 @@ a|
 
 [.tblbasic]
 [.tblDownload]
-[width="100%",cols="25%,25%,25%,25%",]
+[width="100%",cols="25%,25%,25%,25%",options="header",]
 |===
 |Installer Images |Virtual Machine Images |SD Card Images |Documentation
 a|