Reformat code and comments in lib/utf8.c
Reformat code and comments in lib/utf8.c

The utf8d[] table was originally copied from:

  http://bjoern.hoehrmann.de/utf-8/decoder/dfa/

At some point during development, the author of libgumbo ruined the
formatting of the entire codebase with the awful, broken tool known as
"clang-format". This restores the proper formatting of the table from
the original.

craigbarnes/lua-gumbo,craigbarnes/lua-gumbo,craigbarnes/lua-gumbo