clang-format: [JS] Fix spacing in dict literals.

Before:
  someVariable = {'a':[{}]};

After:
  someVariable = {'a': [{}]};

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@208403 91177308-0d34-0410-b5e6-96231b3b80d8