Fix min_ident_chars: don't lint on non-single-char-params in trait method declaration

Author: t-webber

clippy_lints/src/min_ident_chars.rs

@@ -87,7 +87,10 @@ impl LateLintPass<'_> for MinIdentChars {
         if matches!(&item.kind, rustc_hir::TraitItemKind::Fn(_, _)) {
             let param_names = cx.tcx.fn_arg_idents(item.owner_id.to_def_id());
             for ident in param_names.iter().flatten() {
-                emit_min_ident_chars(self, cx, ident.as_str(), ident.span);
+                let str = ident.as_str();
+                if self.is_ident_too_short(cx, str, ident.span) {
+                    emit_min_ident_chars(self, cx, str, ident.span);
+                }
             }
         }