doc: use singular form of repeatable path arg

This is more correct because the <path>... doc syntax already indicates
that the arg is "array-type".  It's how other tools do it.  Finally, the
later document text mentions 'path' arguments, while it doesn't mention
'paths'.

Signed-off-by: Britton Leo Kerin <britton.kergin@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: bkerin

Documentation/git-bisect.txt

@@ -17,7 +17,7 @@ The command takes various subcommands, and different options depending
 on the subcommand:
 
  git bisect start [--term-(new|bad)=<term-new> --term-(old|good)=<term-old>]
-		  [--no-checkout] [--first-parent] [<bad> [<good>...]] [--] [<paths>...]
+		  [--no-checkout] [--first-parent] [<bad> [<good>...]] [--] [<path>...]
  git bisect (bad|new|<term-new>) [<rev>]
  git bisect (good|old|<term-old>) [<rev>...]
  git bisect terms [--term-good | --term-bad]