fix: syntax highlighting for !, !!, and != (#183)

Author: sansx

grammars/grammar-tact.json

@@ -175,7 +175,7 @@
       ]
     },
     "operator-logic": {
-      "match": "(==|<(?!<)|<=|>(?!>)|>=|\\&\\&|\\|\\||\\:(?!=)|\\?)",
+      "match": "(==|<(?!<)|<=|>(?!>)|>=|\\&\\&|\\|\\||\\:(?!=)|\\?|!|!!|!=)",
       "name": "keyword.operator.logic"
     },
     "operator-mapping": {