indent: Move comments inside the block.

This fixes a few

if (foo)
  /* A comment
     with several
     lines.  */
  {
  }

Which has the problem that the block is visually not related to the
"if" and might thus falsely be considered a standalone block.

Also adds a asterisk on the left side of longer comments.

• Signed-off-by: Werner Koch <wk@gnupg.org>