fix(docs): fix broken markdown links (#7081)

* fix(docs): fix markdown docs links

More than half of them were actually valid links but, due to missing file extensions were flagged as invalid. I added a file extension, so it should pass now.

* Updated docgen to include extension

scripts/clidocgen/gen.go

@@ -55,10 +55,7 @@ func init() {
 				return fmt.Sprintf("<code>%s</code>", s)
 			},
 			"commandURI": func(cmd *clibase.Cmd) string {
-				return strings.TrimSuffix(
-					fmtDocFilename(cmd),
-					".md",
-				)
+				return fmtDocFilename(cmd)
 			},
 			"fullName": fullName,
 			"tableHeader": func() string {