many-to-one 1/9: Rename Rule::code to Rule::noqa_code

Post this commit series several codes can be mapped to a single rule,
this commit therefore renames Rule::code to Rule::noqa_code,
which is the code that --add-noqa will add to ignore a rule.

crates/ruff_macros/src/define_rule_mapping.rs

@@ -106,7 +106,7 @@ pub fn define_rule_mapping(mapping: &Mapping) -> proc_macro2::TokenStream {
                 match self { #rule_autofixable_match_arms }
             }
 
-            pub fn code(&self) -> &'static str {
+            pub fn noqa_code(&self) -> &'static str {
                 match self { #rule_code_match_arms }
             }