[PATCH] kernel-doc: fix some odd spacing issues

- in man and text mode output, if the function return type is empty (like it
  is for macros), don't print the return type and a following space; this
  fixes an output malalignment;

- in the function short description, strip leading, trailing, and multiple
  embedded spaces (to one space); this makes function name/description output
  spacing consistent;

- fix a comment typo;

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>