fix typo, direct link to css subdir (fewer clicks) (#1257)

Author: tantek

README.md

@@ -4,15 +4,16 @@ csswg-test has moved
 As of 28 March 2017, this repo is no more. RIP, csswg-test.
 
 It has now been merged into [web-platform-tests][] and all tests formerly in
-this repository can be found in the `css` subdirectory.
+this repository can be found in the `css` subdirectory:
+* https://github.com/w3c/web-platform-tests/tree/master/css
 
 Issues and pull requests on this repository are kept for historical interest
 only; no new issues should be opened: they will be as heard as a tree falling
 in a abandoned forest.
 
 If you have an existing pull request open here, feel free to push new changes
 to it until it is ready to merge. If you were about to open a pull request
-here, [rebase it onto web-platform-tests][moving-old-branches]) and open it
+here, [rebase it onto web-platform-tests][moving-old-branches], and open it
 there.