Use ;; instead of ; for line comments (#115036)

LISPs in general and Clojure in particular by convention uses double semicolons
for regular line comments. Single semicolons are reserved for trailing comments
at the end of a line, and are treated (aligned) differently in some editors,
notably Emacs.
Co-authored-by: NArne Brasseur <arne@arnebrasseur.net>

extensions/clojure/language-configuration.json

 {
 	"comments": {
-		"lineComment": ";"
+		"lineComment": ";;"
 	},
 	"brackets": [
 		["{", "}"],