rubocop: Trim Naming/MethodParameterName allowlist based on defaults

- These are already included in
  6136ffd91e/config/default.yml (L2834-L2862)
  upstream default allowed method names, so we don't need them here too.
- Practically this makes no difference since the `inherit_mode` is
  `merge` it'll just merge the two, but for tidiness I thought I'd do
  this anyway since the duplication annoyed me.

Library/.rubocop.yml

@@ -192,7 +192,6 @@ Naming/MethodParameterName:
     [
       "a",
       "b",
-      "cc",
       "c1",
       "c2",
       "d",
@@ -200,7 +199,6 @@ Naming/MethodParameterName:
       "f",
       "ff",
       "fn",
-      "id",
       "o",
       "p",
       "pr",