[Generator] Improve parameter handling of MIME types in content types #114

Job	Run time
Swift 6 Language Mode	0s
Compatibility test	4m 58s
Example packages / Linux (5.8)	24s
Soundness / API breakage check	2m 46s
Example packages / Linux (5.9)	16m 51s
Integration test / Linux (5.8)	22s
Integration test / Linux (5.9)	1m 32s
Example packages / Linux (5.10)	15m 7s
Soundness / Documentation check	1m 39s
Integration test / Linux (5.10)	1m 41s
Example packages / Linux (nightly-6.0)	22m 22s
Integration test / Linux (nightly-6.0)	2m 0s
Example packages / Linux (nightly-main)	27s
Integration test / Linux (nightly-main)	28s
Soundness / Unacceptable language check	7s
Soundness / Broken symlinks check	5s
Soundness / Format check	38s
Soundness / License headers check	5s
Soundness / Shell check	34s
Unit tests / Unit tests / Linux (5.8)	23s
Unit tests / Unit tests / Linux (5.9)	1m 38s
Unit tests / Unit tests / Linux (5.10)	1m 33s
Unit tests / Unit tests / Linux (nightly-6.0)	2m 0s
Unit tests / Unit tests / Linux (nightly-main)	27s
	1h 18m 7s

Provide feedback