bazel: Add a link in docs to bazel targets doc

The official Bazel user guide has a great section on target patterns
that fits in well with the examples we give for running tests.

Change-Id: I0caa1d73a652adc5d2b8858e0ef73bddcda934f9
diff --git a/Documentation/dev-bazel.txt b/Documentation/dev-bazel.txt
index 0ae038a..9d29980 100644
--- a/Documentation/dev-bazel.txt
+++ b/Documentation/dev-bazel.txt
@@ -376,6 +376,11 @@
 * server
 * ssh
 
+Bazel itself supports a multitude of ways to
+link:https://docs.bazel.build/versions/master/guide.html#specifying-targets-to-build[specify targets,role=external,window=_blank]
+for fine-grained test selection that can be combined with many of the examples
+above.
+
 [[elasticsearch]]
 === Elasticsearch