gallium/docs: use none for highlight_language

We have much more blocks that are of no particular language (mostly
custom ASM variants), so let's instead opt in if we want
syntax-highlighting.

Acked-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Acked-by: Eric Engestrom <eric@engestrom.ch>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5691>

src/gallium/docs/source/conf.py

@@ -84,7 +84,7 @@ exclude_trees = []
 pygments_style = 'sphinx'
 
 # The language for highlighting source code.
-highlight_language = 'c'
+highlight_language = 'none'
 
 # A list of ignored prefixes for module index sorting.
 #modindex_common_prefix = []

src/gallium/docs/source/drivers/freedreno/ir3-notes.rst

@@ -133,7 +133,7 @@ In addition there are various util macros/functions to simplify manipulation/tra
 
 For example:
 
-::
+.. code-block:: c
 
   foreach_ssa_src_n(src, i, instr) {
     unsigned d = delay_calc_srcn(ctx, src, instr, i);