[clang-format] Use SpacesBeforeTrailingComments for "option" directive

Summary:
AnnotatingParser::next() is needed to implicitly set TT_BlockComment
versus TT_LineComment.  On most other paths through
AnnotatingParser::parseLine(), all tokens are consumed to achieve that.
This change updates one place where this wasn't done.

Contributed by @dchai!

Reviewers: krasimir

Reviewed By: krasimir

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D60541

llvm-svn: 358275