clang-format: [JS] handle `for` as object label.

[mprobst]

Summary

Previously, clang-format would fail formatting {for: 1}.

[djasper]

unittests/Format/FormatTestJS.cpp

326

wat?

[mprobst]

• fix test

unittests/Format/FormatTestJS.cpp

326

Whoops, only fixed the code, not the test...

lib/Format/TokenAnnotator.cpp

case tok::kw_while:
       if (CurrentToken && CurrentToken->is(tok::l_paren)) {
         next();
         if (!parseParens(/*LookForDecls=*/true))
           return false;
       }
       break;
     case tok::kw_for:
       if (Style.Language == FormatStyle::LK_JavaScript) {
-        if (Tok->Previous && Tok->Previous->is(tok::period))
+        // x.for and {for: ...}
+        if ((Tok->Previous && Tok->Previous->is(tok::period)) ||
+            (Tok->Next && Tok->Next->is(tok::colon)))
           break;
         // JS' for await ( ...
         if (CurrentToken && CurrentToken->is(Keywords.kw_await))
           next();
       }
       Contexts.back().ColonIsForRangeExpr = true;
       next();
       if (!parseParens())

unittests/Format/FormatTestJS.cpp

TEST_F(FormatTestJS, ReservedWords) {
   verifyFormat("interface = 2;");
   verifyFormat("x = interface instanceof y;");
   verifyFormat("interface Test {\n"
                "  x: string;\n"
                "  switch: string;\n"
                "  case: string;\n"
                "  default: string;\n"
                "}\n");
+  verifyFormat("const Axis = {\n"
+               "  for: 'for',\n"
+               "  x: 'x'\n"
+               "};",
+               "const Axis = {for: 'for', x:   'x'};");
 }
 
 TEST_F(FormatTestJS, ReservedWordsMethods) {
   verifyFormat(
       "class X {\n"
       "  delete() {\n"
       "    x();\n"
       "  }\n"