[clang-format] Do not break after ObjC category open paren
Summary:
Previously, `clang-format` would break Objective-C
category extensions after the opening parenthesis to avoid
breaking the protocol list:
```
% echo "@interface
ccccccccccccc (
ccccccccccc) <
ccccccccccccc> { }" | \
clang-format -assume-filename=foo.h -style="{BasedOnStyle: llvm, \
ColumnLimit: 40}"
@interface
ccccccccccccc (
ccccccccccc) <
ccccccccccccc> {
}
```
This looks fairly odd, as we could have kept the category extension
on the previous line.
Category extensions are a single item, so they are generally very
short compared to protocol lists. We should prefer breaking after the
opening `<` of the protocol list over breaking after the opening `(`
of the category extension.
With this diff, we now avoid breaking after the category extension's
open paren, which causes us to break after the protocol list's
open angle bracket:
```
% echo "@interface
ccccccccccccc (
ccccccccccc) <
ccccccccccccc> { }" | \
./bin/clang-format -assume-filename=foo.h -style="{BasedOnStyle: llvm, \
ColumnLimit: 40}"
@interface
ccccccccccccc (
ccccccccccc) <
ccccccccccccc> {
}
```
Test Plan: New test added. Confirmed test failed before diff and
passed after diff by running:
% make -j16 FormatTests && ./tools/clang/unittests/Format/FormatTests
Reviewers: djasper, jolesiak
Reviewed By: djasper
Subscribers: klimek, cfe-commits
Differential Revision: https://reviews.llvm.org/D45526
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@329919
91177308-0d34-0410-b5e6-
96231b3b80d8