refactor: extract mun_hir_input #1908

Job	Run time
Check	3m 15s
Test C++ Runtime (ubuntu-latest)	5m 59s
Doctest Rust (ubuntu-latest)	3m 30s
Check Style	31s
Test C++ Runtime (windows-latest)	12m 37s
Test Rust (ubuntu-latest)	6m 41s
Doctest Rust (windows-latest)	7m 36s
Test C++ Runtime (macOS-latest)	5m 33s
Test Rust (windows-latest)	12m 15s
Test mdbook	4m 16s
Test Rust (macOS-latest)	4m 59s
Doctest Rust (macOS-latest)	2m 57s
	1h 10m 9s

Provide feedback