We are accidentally grabbing more docs than we asked for

[jade]

nix-repl> builtins.doc n.lib.fixedWidthString
...
...
...
   Example:
   with_Feature true "shared" "foo"
   => "--with-shared=foo"
   with_Feature false "shared" (throw "ignored")
   => "--without-shared"
   Create a fixed width string with additional prefix to match
   required width.

   This function will fail if the input string is longer than the
   requested length.

   Type: fixedWidthString :: int -> string -> string

   Example:
   fixedWidthString 5 "0" (toString 15)
   => "00015"
func = width: filler: str: ...
# /home/lf/dev/nixpkgs/lib/strings.nix:596
null

I am pretty sure this is a regression since we relaxed the comment finding.