docs: Fix outdated speaker_layout enum

Commit 67e48ecc2ca033020210f3aae05617195d37e248 changed this enum from
`SPEAKERS_QUAD` to `SPEAKERS_4POINT0` but did not update the docs.

docs/sphinx/reference-libobs-media-io.rst

@@ -220,7 +220,7 @@ Audio Handler
    - SPEAKERS_MONO
    - SPEAKERS_STEREO
    - SPEAKERS_2POINT1
-   - SPEAKERS_QUAD
+   - SPEAKERS_4POINT0
    - SPEAKERS_4POINT1
    - SPEAKERS_5POINT1
    - SPEAKERS_5POINT1_SURROUND

docs/sphinx/reference-outputs.rst

@@ -733,7 +733,7 @@ Functions used by outputs
            SPEAKERS_MONO,
            SPEAKERS_STEREO,
            SPEAKERS_2POINT1,
-           SPEAKERS_QUAD,
+           SPEAKERS_4POINT0,
            SPEAKERS_4POINT1,
            SPEAKERS_5POINT1,
            SPEAKERS_5POINT1_SURROUND,