Add comment language injection (#43)

Addresses thedadams/zed-comment#14

---------

Signed-off-by: Donnie Adams <donnie@thedadams.com>
Co-authored-by: MrSubidubi <dev@bahn.sh>

Author: thedadams

languages/swift/injections.scm

@@ -2,3 +2,11 @@
 
 ((regex_literal) @injection.content
  (#set! injection.language "regex"))
+
+(
+  [
+    (comment)
+    (multiline_comment)
+  ] @injection.content
+ (#set! injection.language "comment")
+)