Clarify that Bazel can be run from a subdirectory of the workspace root, not just the root itself

RELNOTES: None
PiperOrigin-RevId: 310889126

site/docs/output_directories.md

diff --git a/site/docs/output_directories.md b/site/docs/output_directories.md
index bdb7a3f..b49e9a8 100644
--- a/site/docs/output_directories.md
+++ b/site/docs/output_directories.md
@@ -24,8 +24,9 @@
 
 The solution that's currently implemented:
 
-* Bazel must be invoked from a directory containing a WORKSPACE file. It reports
-  an error if it is not. We call this the _workspace directory_.
+* Bazel must be invoked from a directory containing a WORKSPACE file (the
+  "_workspace directory_"), or a subdirectory thereof. It reports an error if it
+  is not.
 * The _outputRoot_ directory defaults to `~/.cache/bazel` on Linux,
   `/private/var/tmp` on macOS, and on Windows it defaults to `%HOME%` if set,
   else `%USERPROFILE%` if set, else the result of calling