Treat nameof as a keyword

Author: williewillus

hack-mode.el

@@ -599,7 +599,7 @@ If PROPERTIZE-TAGS is non-nil, apply `hack-xhp-tag' to tag names."
      "endforeach" "endif" "endswitch" "endwhile" "eval" "exit" "extends"
      "final" "finally" "for" "foreach" "function" "global" "goto" "if"
      "implements" "include" "include_once" "insteadof"
-     "interface" "is" "isset" "list" "namespace" "new" "parent"
+     "interface" "is" "isset" "list" "nameof" "namespace" "new" "parent"
      "print" "private" "protected" "public" "internal"
      "require" "require_once"
      "return" "self" "static" "switch" "throw" "trait"