clean code for man page option

before, i thought pass param like c, one function to one function.
but since v:count1 is always stored, so doesn't need pass it as
parameter.

still in ref.vim need a special judge for man, because in man.vim it
doesn't the query body from :Ref man keyword, or Shift+k with v:count1

i test at most case, so i think the code is stable.

Signed-off-by: xiehuc <xiehuc@gmail.com>