clang-format: [JS] handle semis in generic types.
Summary:
TypeScript generic type arguments can contain object (literal) types,
which in turn can contain semicolons:
const x: Array<{a: number; b: string;} = [];
Previously, clang-format would incorrectly categorize the braced list as
a block and terminate the line at the openening `{`, and then format the
entire expression badly.
With this change, clang-format recognizes `<` preceding a `{` as
introducing a type expression. In JS, `<` comparison with an object
literal can never be true, so the chance of introducing false positives
here is very low.
Reviewers: djasper
Subscribers: klimek, cfe-commits
Differential Revision: https://reviews.llvm.org/D40424
llvm-svn: 318975