clang-tidy: enable more checks, fix fallouts

- enable three checks:
  - bugprone-invalid-enum-default-initialization
  - bugprone-sizeof-expression
  - readability-inconsistent-declaration-parameter-name (strict)
- fix remaining discrepancies with arg names in prototypes
  and implementation, in strict mode.
- document reason for some checks tested but not enabled.

Closes #20794

lib/rand.h

@@ -25,7 +25,7 @@
  ***************************************************************************/
 CURLcode Curl_rand_bytes(struct Curl_easy *data,
 #ifdef DEBUGBUILD
-                         bool allow_env_override,
+                         bool env_override,
 #endif
                          unsigned char *rnd, size_t num);