[`flake8-simplify`] Make example error out-of-the-box (`SIM401`) (#19110)
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## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
Part of #18972
This PR makes [enumerate-for-loop [if-else-block-instead-of-dict-get
(SIM401)](https://docs.astral.sh/ruff/rules/if-else-block-instead-of-dict-get/#if-else-block-instead-of-dict-get-sim401)'s
example error out-of-the-box
[Old example](https://play.ruff.rs/635629eb-7146-45a8-9e0c-4a0aa9446ded)
```py
if "bar" in foo:
value = foo["bar"]
else:
value = 0
```
[New example](https://play.ruff.rs/a1227ec9-05c2-4a22-800d-c76cb7abe249)
```py
foo = {}
if "bar" in foo:
value = foo["bar"]
else:
value = 0
```
The "Use instead" section was also updated similarly.
The docs for `SIM401` also has another section on the preview ternary
version, but it does not seem to check that the variable is a dict
(bug?) https://play.ruff.rs/c0feada8-a7fe-43f7-b57e-c10520fdcdca
## Test Plan
<!-- How was it tested? -->
N/A, no functionality/tests affected
ruff
26bb8f7b - [`flake8-simplify`] Make example error out-of-the-box (`SIM401`) (#19110)
