[lit] NFC: Document missing result codes

These result codes already exist, but they were not documented. I assume
this is an oversight when adding these result codes.

Author: ldionne

llvm/docs/CommandGuide/lit.rst

@@ -251,12 +251,17 @@ convenient and flexible support for out-of-tree builds.
 TEST STATUS RESULTS
 -------------------
 
-Each test ultimately produces one of the following six results:
+Each test ultimately produces one of the following eight results:
 
 **PASS**
 
  The test succeeded.
 
+**FLAKYPASS**
+
+ The test succeeded after being re-run more than once. This only applies to
+ tests containing an ``ALLOW_RETRIES:`` annotation.
+
 **XFAIL**
 
  The test failed, but that is expected.  This is used for test formats which allow
@@ -283,6 +288,11 @@ Each test ultimately produces one of the following six results:
  The test is not supported in this environment.  This is used by test formats
  which can report unsupported tests.
 
+**TIMEOUT**
+
+ The test was run, but it timed out before it was able to complete. This is
+ considered a failure.
+
 Depending on the test format tests may produce additional information about
 their status (generally only for failures).  See the :ref:`output-options`
 section for more information.