Bug 1511181 - Quick fix for .hg-format-source that has an empty line. r=ehsan, a=aryx

--HG--
extra : amend_source : bc08a6439f912240146a7ce2718e4e2ffeb5f655

.hg-format-source

-
 {"configpaths": [".clang-format", ".clang-format-ignore"], "pattern": "glob:uriloader/**", "tool": "clang-format"}
 {"configpaths": [".clang-format", ".clang-format-ignore"], "pattern": "glob:media/**", "tool": "clang-format"}
 {"configpaths": [".clang-format", ".clang-format-ignore"], "pattern": "glob:docshell/**", "tool": "clang-format"}