Merge branch 'pw/allow-compound-literals'

The coding guidelines have been updated to officially allow the use
of C99 compound literals, as the test balloon has been flying
without issues since late 2024.

* pw/allow-compound-literals:
  CodingGuidelines: allow compound literals

Documentation/CodingGuidelines

@@ -311,13 +311,8 @@ For C programs:
    . since late 2023 with 8277dbe987 we have been using the bool type
      from <stdbool.h>.
 
-   C99 features we have test balloons for:
-
-   . since late 2024 with v2.48.0-rc0~20, we have test balloons for
-     compound literal syntax, e.g., (struct foo){ .member = value };
-     our hope is that no platforms we care about have trouble using
-     them, and officially adopt its wider use in mid 2026.  Do not add
-     more use of the syntax until that happens.
+   . since late 2024 with v2.48.0-rc0~20, we have been using compound
+     literals, e.g., (struct foo){ .member = value };
 
    New C99 features that we cannot use yet: