clang-format: [JS] do not wrap after "readonly".

[mprobst]

Summary

Breaks after "readonly" trigger automatic semicolon insertion in field
declarations.

[mprobst]

use a less ominous looking width, 12 doesn't actually carry any significance here.

[krasimir]

Looks good!

lib/Format/FormatToken.h

AdditionalKeywords(IdentifierTable &IdentTable) {
     kw_finally = &IdentTable.get("finally");
     kw_from = &IdentTable.get("from");
     kw_function = &IdentTable.get("function");
     kw_get = &IdentTable.get("get");
     kw_import = &IdentTable.get("import");
     kw_is = &IdentTable.get("is");
     kw_let = &IdentTable.get("let");
     kw_module = &IdentTable.get("module");
+    kw_readonly = &IdentTable.get("readonly");
     kw_set = &IdentTable.get("set");
     kw_type = &IdentTable.get("type");
     kw_var = &IdentTable.get("var");
     kw_yield = &IdentTable.get("yield");
 
     kw_abstract = &IdentTable.get("abstract");
     kw_assert = &IdentTable.get("assert");
     kw_extends = &IdentTable.get("extends");
AdditionalKeywords(IdentifierTable &IdentTable) {
     kw_qsignals = &IdentTable.get("Q_SIGNALS");
     kw_slots = &IdentTable.get("slots");
     kw_qslots = &IdentTable.get("Q_SLOTS");
 
     // Keep this at the end of the constructor to make sure everything here is
     // already initialized.
     JsExtraKeywords = std::unordered_set<IdentifierInfo *>(
         {kw_as, kw_async, kw_await, kw_declare, kw_finally, kw_from,
-         kw_function, kw_get, kw_import, kw_is, kw_let, kw_module, kw_set,
-         kw_type, kw_var, kw_yield,
+         kw_function, kw_get, kw_import, kw_is, kw_let, kw_module, kw_readonly,
+         kw_set, kw_type, kw_var, kw_yield,
          // Keywords from the Java section.
          kw_abstract, kw_extends, kw_implements, kw_instanceof, kw_interface});
   }
 
   // Context sensitive keywords.
   IdentifierInfo *kw_final;
   IdentifierInfo *kw_override;
   IdentifierInfo *kw_in;
struct AdditionalKeywords {
   IdentifierInfo *kw_finally;
   IdentifierInfo *kw_from;
   IdentifierInfo *kw_function;
   IdentifierInfo *kw_get;
   IdentifierInfo *kw_import;
   IdentifierInfo *kw_is;
   IdentifierInfo *kw_let;
   IdentifierInfo *kw_module;
+  IdentifierInfo *kw_readonly;
   IdentifierInfo *kw_set;
   IdentifierInfo *kw_type;
   IdentifierInfo *kw_var;
   IdentifierInfo *kw_yield;
 
   // Java keywords.
   IdentifierInfo *kw_abstract;
   IdentifierInfo *kw_assert;

lib/Format/TokenAnnotator.cpp

if (Left.isOneOf(Keywords.kw_throws, Keywords.kw_extends,
                      Keywords.kw_implements))
       return false;
     if (Right.isOneOf(Keywords.kw_throws, Keywords.kw_extends,
                       Keywords.kw_implements))
       return true;
   } else if (Style.Language == FormatStyle::LK_JavaScript) {
     const FormatToken *NonComment = Right.getPreviousNonComment();
     if (NonComment &&
-        NonComment->isOneOf(
-            tok::kw_return, tok::kw_continue, tok::kw_break, tok::kw_throw,
-            Keywords.kw_interface, Keywords.kw_type, tok::kw_static,
-            tok::kw_public, tok::kw_private, tok::kw_protected,
-            Keywords.kw_abstract, Keywords.kw_get, Keywords.kw_set))
+        NonComment->isOneOf(tok::kw_return, tok::kw_continue, tok::kw_break,
+                            tok::kw_throw, Keywords.kw_interface,
+                            Keywords.kw_type, tok::kw_static, tok::kw_public,
+                            tok::kw_private, tok::kw_protected,
+                            Keywords.kw_readonly, Keywords.kw_abstract,
+                            Keywords.kw_get, Keywords.kw_set))
       return false; // Otherwise automatic semicolon insertion would trigger.
     if (Left.is(TT_JsFatArrow) && Right.is(tok::l_brace))
       return false;
     if (Left.is(TT_JsTypeColon))
       return true;
     if (Right.NestingLevel == 0 && Right.is(Keywords.kw_is))
       return false;
     if (Left.is(Keywords.kw_in))

unittests/Format/FormatTestJS.cpp

TEST_F(FormatTestJS, WrapRespectsAutomaticSemicolonInsertion) {
   verifyFormat("break aaaaa;", getGoogleJSStyleWithColumns(10));
   verifyFormat("throw aaaaa;", getGoogleJSStyleWithColumns(10));
   verifyFormat("aaaaaaaaa++;", getGoogleJSStyleWithColumns(10));
   verifyFormat("aaaaaaaaa--;", getGoogleJSStyleWithColumns(10));
   verifyFormat("return [\n"
                "  aaa\n"
                "];",
                getGoogleJSStyleWithColumns(12));
+  verifyFormat("class X {\n"
+               "  readonly ratherLongField =\n"
+               "      1;\n"
+               "}",
+               "class X {\n"
+               "  readonly ratherLongField = 1;\n"
+               "}",
+               getGoogleJSStyleWithColumns(20));
 }
 
 TEST_F(FormatTestJS, AutomaticSemicolonInsertionHeuristic) {
   verifyFormat("a\n"
                "b;",
                " a \n"
                " b ;");
   verifyFormat("a()\n"