man: add section delimiters in weston.ini

These added lines are comments (do not affect output) that make it
easier to browse this file and find the section headings.

Removal of the preceding empty lines on two of the section headers
remove a blank line from PDF output. The blank line was kind of nice,
but presumably .SH should add any necessary blanks before a new section
heading. Now all the section headings have the same vertical space to
the preceding content in PDF.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>