ci: Also rustfmt binaries

The standard name for an executable is main.rs.  Also fix the rusticl
docs while we're at it.

Reviewed-by: Eric Engestrom <eric@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/26546>

.gitlab-ci/test/gitlab-ci.yml

@@ -46,6 +46,7 @@ rustfmt:
     - shopt -s globstar
     - rustfmt --version
     - rustfmt --verbose src/**/lib.rs
+    - rustfmt --verbose src/**/main.rs
 
 clang-format:
   extends:

docs/rusticl.rst

@@ -86,7 +86,7 @@ that add new features should be ran against the appropriate conformance
 tests.
 
 Also, make sure the formatting is in order before submitting code. That
-can easily be done via ``git ls-files */{lib,app}.rs | xargs rustfmt``.
+can easily be done via ``git ls-files */{lib,main}.rs | xargs rustfmt``.
 
 When submitting Merge Requests or filing bugs related to Rusticl, make
 sure to add the ``Rusticl`` label so people subscribed to that Label get