clang-format: [JS] Improve line-wrapping behavior of template strings.

clang-format: [JS] Improve line-wrapping behavior of template strings.

Specifically, similar to other blocks, clang-format now wraps both
after "${" and before the corresponding "}", if the contained
expression spans multiple lines.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@295663 91177308-0d34-0410-b5e6-96231b3b80d8