Add grammar docstrings to QASM3 parser #9612

Job	Run time
Clippy	31s
Build and test (windows-latest)	12m 0s
Format	18s
Format Q# Files	43s
Build and test (ubuntu-latest)	5m 26s
Build and test (macos-14)	8m 53s
Integration tests (windows-latest)	13m 52s
Rust Unit tests (windows-latest)	8m 25s
Integration tests (ubuntu-latest)	8m 17s
Check web files	32s
Integration tests (macos-14)	16m 4s
Rust Unit tests (ubuntu-latest)	3m 24s
Rust Unit tests (macos-14)	5m 56s
Status Check	1s
	1h 24m 22s

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