Error for assignment of functional Enum to variable of different name

[hauntsaninja]

Relates to discussion in
https://discuss.python.org/t/draft-of-typing-spec-chapter-for-enums/43496/11

[github-actions]

Diff from mypy_primer, showing the effect of this PR on open source code:

psycopg (https://github.com/psycopg/psycopg)
+ tests/types/test_enum.py:309: error: String argument 1 "RenamedEnum" to enum.Enum(...) does not match variable name "enum"  [misc]
+ tests/types/test_enum.py:321: error: String argument 1 "LargerEnum" to enum.Enum(...) does not match variable name "enum"  [misc]
+ tests/types/test_enum.py:336: error: String argument 1 "SmallerEnum" to enum.Enum(...) does not match variable name "enum"  [misc]

jax (https://github.com/google/jax)
+ jax/_src/pretty_printer.py:150: error: String argument 1 "_Color" to enum.Enum(...) does not match variable name "Color"  [misc]
+ jax/_src/pretty_printer.py:152: error: String argument 1 "_Intensity" to enum.Enum(...) does not match variable name "Intensity"  [misc]

graphql-core (https://github.com/graphql-python/graphql-core)
+ tests/type/test_definition.py:701: error: String argument 1 "Colors" to enum.Enum(...) does not match variable name "colors"  [misc]
+ tests/type/test_definition.py:709: error: String argument 1 "Colors" to enum.Enum(...) does not match variable name "colors"  [misc]
+ tests/type/test_definition.py:717: error: String argument 1 "Colors" to enum.Enum(...) does not match variable name "colors"  [misc]
+ tests/type/test_definition.py:725: error: String argument 1 "Colors" to enum.Enum(...) does not match variable name "colors"  [misc]