RELNOTES: Document interaction between test_suite and target exclusions

Now with more accuracy.

PiperOrigin-RevId: 174873635
diff --git a/site/docs/user-manual.html b/site/docs/user-manual.html
index 16655a5..41fd48c 100644
--- a/site/docs/user-manual.html
+++ b/site/docs/user-manual.html
@@ -455,6 +455,14 @@
   under 'contrib' depends on something under 'contrib' though, in order to
   build the former bazel has to build the latter too. As usual, the '--' is
   required to prevent '-f' from being interpreted as an option.
+
+  When running the test command, test suite expansion is applied to each target
+  pattern in sequence as the set of targets is evaluated. This means that
+  individual tests from a test suite can be excluded by a later target pattern.
+  It also means that an exclusion target pattern which matches a test suite will
+  exclude all tests which that test suite references. (Targets that would be
+  matched by the list of target patterns without any test suite expansion are
+  also built unless --build_tests_only is set.)
 </pre>
 <p>
   Whereas <a href="build-ref.html#labels">labels</a> are used