Remove `typing.Self` workaround

Remove ``typing.Self`` workaround, now using :pep:`673` for most methods
that return ``Self``. Pull request courtesy Yurii Karabas.

Fixes: #9254
Closes: #9255
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/9255
Pull-request-sha: 2947df8ada79f5c3afe9c838e65993302199c2f7

Change-Id: Ic32015ad52e95a61f3913d43ea436aa9402804df

2 files changed, 6 insertions, 14 deletions

diff --git a/lib/sqlalchemy/dialects/mysql/dml.py b/lib/sqlalchemy/dialects/mysql/dml.py
index 7fdd362b9..7c724c6f1 100644
--- a/lib/sqlalchemy/dialects/mysql/dml.py
+++ b/lib/sqlalchemy/dialects/mysql/dml.py
@@ -6,8 +6,6 @@
 # mypy: ignore-errors
 
 
-import typing
-
 from ... import exc
 from ... import util
 from ...sql.base import _exclusive_against
@@ -16,6 +14,7 @@ from ...sql.base import ColumnCollection
 from ...sql.dml import Insert as StandardInsert
 from ...sql.elements import ClauseElement
 from ...sql.expression import alias
+from ...util.typing import Self
 
 
 __all__ = ("Insert", "insert")
@@ -40,9 +39,6 @@ def insert(table):
     return Insert(table)
 
 
-SelfInsert = typing.TypeVar("SelfInsert", bound="Insert")
-
-
 class Insert(StandardInsert):
     """MySQL-specific implementation of INSERT.
 
@@ -102,7 +98,7 @@ class Insert(StandardInsert):
             "has an ON DUPLICATE KEY clause present"
         },
     )
-    def on_duplicate_key_update(self: SelfInsert, *args, **kw) -> SelfInsert:
+    def on_duplicate_key_update(self, *args, **kw) -> Self:
         r"""
         Specifies the ON DUPLICATE KEY UPDATE clause.
 
diff --git a/lib/sqlalchemy/dialects/mysql/expression.py b/lib/sqlalchemy/dialects/mysql/expression.py
index 016ea251c..c5bd0be02 100644
--- a/lib/sqlalchemy/dialects/mysql/expression.py
+++ b/lib/sqlalchemy/dialects/mysql/expression.py
@@ -6,8 +6,6 @@
 # mypy: ignore-errors
 
 
-import typing
-
 from ... import exc
 from ... import util
 from ...sql import coercions
@@ -16,9 +14,7 @@ from ...sql import operators
 from ...sql import roles
 from ...sql.base import _generative
 from ...sql.base import Generative
-
-
-Selfmatch = typing.TypeVar("Selfmatch", bound="match")
+from ...util.typing import Self
 
 
 class match(Generative, elements.BinaryExpression):
@@ -110,7 +106,7 @@ class match(Generative, elements.BinaryExpression):
         super().__init__(left, against, operators.match_op, modifiers=flags)
 
     @_generative
-    def in_boolean_mode(self: Selfmatch) -> Selfmatch:
+    def in_boolean_mode(self) -> Self:
         """Apply the "IN BOOLEAN MODE" modifier to the MATCH expression.
 
         :return: a new :class:`_mysql.match` instance with modifications
@@ -121,7 +117,7 @@ class match(Generative, elements.BinaryExpression):
         return self
 
     @_generative
-    def in_natural_language_mode(self: Selfmatch) -> Selfmatch:
+    def in_natural_language_mode(self) -> Self:
         """Apply the "IN NATURAL LANGUAGE MODE" modifier to the MATCH
         expression.
 
@@ -133,7 +129,7 @@ class match(Generative, elements.BinaryExpression):
         return self
 
     @_generative
-    def with_query_expansion(self: Selfmatch) -> Selfmatch:
+    def with_query_expansion(self) -> Self:
         """Apply the "WITH QUERY EXPANSION" modifier to the MATCH expression.
 
         :return: a new :class:`_mysql.match` instance with modifications