[clang-format] Avoid parsing "requires" as a keyword in non-C++-like languages.

[curdeius]

Summary

Fixes the issue raised post-review in D113319 (cf. https://reviews.llvm.org/D113319#3337485).

[krasimir]

Thank you!

clang/lib/Format/UnwrappedLineParser.cpp

case tok::at:
       default:
         break;
       }
       break;
     case tok::kw_concept:
       parseConcept();
       return;
     case tok::kw_requires: {
+      if (Style.isCpp()) {
         bool ParsedClause = parseRequires();
         if (ParsedClause)
           return;
+      } else {
+        nextToken();
+      }
       break;
     }
     case tok::kw_enum:
       // Ignore if this is part of "template <enum ...".
       if (Previous && Previous->is(tok::less)) {
         nextToken();
         break;
       }

clang/unittests/Format/FormatTestJS.cpp

TEST_F(FormatTestJS, ReservedWords) {
   verifyFormat("x = {\n"
                "  a: 12,\n"
                "  interface: 1,\n"
                "  switch: 1,\n"
                "};");
   verifyFormat("var struct = 2;");
   verifyFormat("var union = 2;");
   verifyFormat("var interface = 2;");
+  verifyFormat("var requires = {};");
   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");