add expr_2021 and pat_param to fragment_specifier

[m4rch3n1ng]

adds expr_2021 and pat_param to possible fragment specifiers. added for backwards compatability for the release of the 2024 edition and the 2021 edition respectively.

diff for #229:

diff

--- .tmp/list.txt	2025-03-07 03:57:30.021995759 +0100
+++ .tmp/list.txt.expr-2021	2025-03-07 03:00:11.631475182 +0100
@@ -211,8 +211,6 @@
 tests/ui/lint/semicolon-in-expressions-from-macros/semicolon-in-expressions-from-macros.rs
 tests/ui/lint/unused/trait-alias-supertrait.rs
 tests/ui/liveness/liveness-upvars.rs
-tests/ui/macros/edition-macro-pats.rs
-tests/ui/macros/expr_2021.rs
 tests/ui/macros/issue-44127.rs
 tests/ui/macros/issue-63102.rs
 tests/ui/macros/issue-77475.rs