doc: Fix the function locations always pointing to master

Instead of revisions as they should. This is (most-likely) caused by a
simple typo, because Hydra is where the revision should come from, but
it doesn't set `.revision` as the attribute, but rather `.rev`!

Changed files
+1 -1
doc
+1 -1
doc/doc-support/lib-function-locations.nix
···
{ pkgs, nixpkgs ? { }, libsets }:
let
-
revision = pkgs.lib.trivial.revisionWithDefault (nixpkgs.revision or "master");
+
revision = pkgs.lib.trivial.revisionWithDefault (nixpkgs.rev or "master");
libDefPos = prefix: set:
builtins.concatMap