Fix keyword color problem - some of keywords were from OCaml (#84)

Author: Abhinandan Arya

grammars/rescript.tmLanguage.json

@@ -15,7 +15,7 @@
     },
     "RE_KEYWORDS": {
       "name": "keyword.control",
-      "match": "\\b(and|as|assert|begin|class|constraint|done|downto|exception|external|fun|functor|inherit|lazy|let|pub|mutable|new|nonrec|object|of|or|pri|rec|then|to|val|virtual|try|catch|finally|do|else|for|if|switch|while|import|library|export|module|in|raise|private)\\b"
+      "match": "\\b(and|as|assert|constraint|downto|else|exception|external|false|for|if|in|include|lazy|let|module|mutable|of|open|rec|switch|to|true|try|type|when|while|with)\\b"
     },
     "RE_LITERAL": {
       "name": "constant.language",