move the version info for build_always* directly into the kwarginfo

Rather than pointlessly evolving it in the exactly one place which it is
used. It's not clear what the purpose for this was.

mesonbuild/interpreter/interpreter.py

@@ -1715,8 +1715,8 @@ external dependencies (including libraries) must go to "dependencies".''')
     @typed_kwargs(
         'custom_target',
         COMMAND_KW,
-        CT_BUILD_ALWAYS.evolve(deprecated='0.47.0'),
+        CT_BUILD_ALWAYS,
-        CT_BUILD_ALWAYS_STALE.evolve(since='0.47.0'),
+        CT_BUILD_ALWAYS_STALE,
         CT_BUILD_BY_DEFAULT,
         CT_INPUT_KW,
         CT_INSTALL_DIR_KW,

mesonbuild/interpreter/type_checking.py

@@ -282,10 +282,15 @@ CT_INSTALL_DIR_KW: KwargInfo[T.List[T.Union[str, bool]]] = KwargInfo(
 
 CT_BUILD_BY_DEFAULT: KwargInfo[T.Optional[bool]] = KwargInfo('build_by_default', (bool, type(None)), since='0.40.0')
 
-CT_BUILD_ALWAYS: KwargInfo[T.Optional[bool]] = KwargInfo('build_always', (bool, NoneType))
+CT_BUILD_ALWAYS: KwargInfo[T.Optional[bool]] = KwargInfo(
+    'build_always', (bool, NoneType),
+     deprecated='0.47.0',
+)
 
 CT_BUILD_ALWAYS_STALE: KwargInfo[T.Optional[bool]] = KwargInfo(
-    'build_always_stale', (bool, NoneType))
+    'build_always_stale', (bool, NoneType),
+    since='0.47.0',
+)
 
 INCLUDE_DIRECTORIES: KwargInfo[T.List[T.Union[str, IncludeDirs]]] = KwargInfo(
     'include_dirs',