docs: Move the conformance and the CI docs to a top level Testing section.

They're related subjects, and deserve top level display.

Reviewed-by: Eric Engestrom <eric@engestrom.ch>
Reviewed-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5510>

docs/ci/index.rst

@@ -1,5 +1,5 @@
-Continuous Integration & Testing
+Continuous Integration
-================================
+======================
 
 
 GitLab CI

docs/contents.rst

@@ -10,7 +10,6 @@
    faq
    relnotes
    thanks
-   conform
 
 .. toctree::
    :maxdepth: 2
@@ -61,13 +60,20 @@
    devinfo
    codingstyle
    submittingpatches
-   ci/index
    releasing
    release-calendar
    sourcedocs
    dispatch
    gallium/index
 
+.. toctree::
+   :maxdepth: 1
+   :caption: Testing
+   :hidden:
+
+   conform
+   ci/index
+
 .. toctree::
    :maxdepth: 1
    :caption: Links