clang-tidy: sync argument names in prototype and definition

Discovered with clang-tidy checker
`readability-inconsistent-declaration-parameter-name`.

Also:
- do not enforce the above because of inconsistencies still present
  between public API prototypes and definitions. (Also betwen man page
  protos, and man page examples, and other parts of the code, e.g.
  `easy` vs `curl` vs `d` vs `handle`) Perhaps subject for a future
  effort:
  https://github.com/curl/curl/actions/runs/22166472728/job/64094691653
- enable and fix `readability-named-parameter` where missing.

Refs:
https://clang.llvm.org/extra/clang-tidy/checks/readability/inconsistent-declaration-parameter-name.html
https://clang.llvm.org/extra/clang-tidy/checks/readability/named-parameter.html

Closes #20624

lib/doh.h

@@ -114,7 +114,7 @@ CURLcode Curl_doh(struct Curl_easy *data, const char *hostname,
                   int port, int ip_version);
 
 CURLcode Curl_doh_is_resolved(struct Curl_easy *data,
-                              struct Curl_dns_entry **dns);
+                              struct Curl_dns_entry **dnsp);
 
 #define DOH_MAX_ADDR  24
 #define DOH_MAX_CNAME 4