Fix broken link.

Both README.md and CONTRIBUTING.md linked to
https://github.com/bazelbuild/eclipse/wiki/Contributing which doesn't
exist.

CONTRIBUTING.md

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index e45d7ce..a0d852b 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -25,5 +25,5 @@
 
 ## Contributing
 
-Please see the [contributing page on the wiki](https://github.com/bazelbuild/eclipse/wiki/Contributing)
+Please see the [Contributing to Bazel](https://bazel.build/contributing.html)
 on more practical matters on how to contribute to e4b.

README.md

diff --git a/README.md b/README.md
index b26e661..7b32508 100644
--- a/README.md
+++ b/README.md
@@ -26,7 +26,8 @@
 
 To import an existing Bazel project or start a new one, go to "New" > "Project..." > "Others".
 
-## Missing features
+## Contributing
 
-See our [contributing page](https://github.com/bazelbuild/eclipse/wiki/Contributing) to get
-some idea on what missing features need help on.
+See our [contributing
+page](https://github.com/bazelbuild/eclipse/blob/master/CONTRIBUTING.md) for how
+to contribute.