bpo-43957: Add a missins space to the new format enum warning (#25770)

Author: pablogsal

Lib/enum.py

@@ -1018,7 +1018,7 @@ def __format__(self, format_spec):
                 import warnings
                 warnings.warn(
                         "in 3.12 format() will use the enum member, not the enum member's value;\n"
-                        "use a format specifier, such as :d for an IntEnum member, to maintain"
+                        "use a format specifier, such as :d for an IntEnum member, to maintain "
                         "the current display",
                         DeprecationWarning,
                         stacklevel=2,