fix(macros): run the ModuleBuilder startup function under #[php_module]

[ptondereau]

Description

#[php_module] set its own startup function after the user's builder code, so a function given to ModuleBuilder::startup_function never ran, and the generated MINIT now calls it after the #[php(startup)] one. The guide also documented #[php_module(startup = ...)] while the macro reads #[php(startup = ...)].

Checklist

• I have read the contribution guidelines and the code of conduct.
• I have added tests that prove my code works as expected.
• I have added documentation if applicable.
• I have added a migration guide if applicable.

[codspeed]

Merging this PR will not alter performance

⚠️ 45 benchmarks spent significant time in system calls

System calls cannot be consistently instrumented, so they are not included in the measure, which understates the real cost. Please switch to the Walltime instrument to accurately measure system calls.

Measurement and system calls

• object_news[100000]
• callback_calls[100000]
• exception_throws[100000]
• property_dumps[100000]
• property_compares[100000]
• string_calls[1]
• string_calls[10]
• object_news[1]
• method_calls[1]
• method_calls[10]
• …and 35 more

✅ 45 untouched benchmarks

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_{Comparing fix/module-builder-startup-function (8c8d93e) with master (1c9a853)}

[coveralls]

Coverage Report for CI Build 37997613183

Coverage remained the same at 74.503%

Details

• Coverage remained the same as the base build.
• Patch coverage: No coverable lines changed in this PR.
• 1 coverage regression across 1 file.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

1 previously-covered line in 1 file lost coverage.

File	Lines Losing Coverage	Coverage
crates/introspection/src/stub.rs	1	88.46%

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Coverage Stats

Relevant Lines:	14602
Covered Lines:	10879
Line Coverage:	74.5%
Coverage Strength:	53.74 hits per line

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💛 - Coveralls