perf: add the checking transition to `may` transition check

[codecov[bot]]

Codecov Report

Base: 98.21% // Head: 98.21% // Increases project coverage by +0.00% :tada:

Coverage data is based on head (c531fb6) compared to base (5694945). Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #592 +/- ## ======================================= Coverage 98.21% 98.21% ======================================= Files 13 13 Lines 2570 2571 +1 ======================================= + Hits 2524 2525 +1 Misses 46 46 ``` | [Impacted Files](https://codecov.io/gh/pytransitions/transitions/pull/592?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None) | Coverage Δ | | |---|---|---| | [transitions/core.py](https://codecov.io/gh/pytransitions/transitions/pull/592/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None#diff-dHJhbnNpdGlvbnMvY29yZS5weQ==) | `100.00% <100.00%> (ø)` | | Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=None)

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