Perl5 support to fold POD blocks

POD blocks (as defined with the =pod and =cut tags) should be foldable.
This documentation format is excessively verbose and clutters the file
when other sections are folded (especially after a "fold all"
operation).

extensions/perl/perl.language-configuration.json

@@ -22,5 +22,11 @@
 		["\"", "\""],
 		["'", "'"],
 		["`", "`"]
-	]
+	],
+	"folding": {
+		"markers": {
+			"start": "^=pod\\s*$",
+			"end": "^=cut\\s*$"
+		}
+	}
 }