[d mode] Fix line comments

Author: abhishekgahlot

mode/d/d.js

@@ -182,7 +182,12 @@ CodeMirror.defineMode("d", function(config, parserConfig) {
       else return ctx.indented + (closing ? 0 : indentUnit);
     },
 
-    electricChars: "{}"
+    electricChars: "{}",
+    blockCommentStart: "/*",
+    blockCommentEnd: "*/",
+    blockCommentContinue: " * ",
+    lineComment: "//",
+    fold: "brace"
   };
 });