feat: support reserved enum values

[anthony-swirldslabs]

Description:
Introducing rudimentary support for reserved enum values. The grammar is able to parse them instead of treating them as regular enum values, and the code generator simply ignores them because PBJ doesn't support unknown enum values currently.

A new enum_reserved.proto is added to integration tests. W/o the fix, the model would produce a generated test that would fail because the output of the JSON codec would differ from what ProtoC generates.

Also, I'm fixing a bunch of useless warning messages that PBJ used to produce for dangling comments and similar items.

Related issue(s):

Fixes #339

Notes for reviewer:
All tests should pass.

Checklist

• Documented (Code comments, README, etc.)
• Tested (unit, integration, etc.)

[github-actions]

JUnit Test Report

   78 files  ±0     78 suites  ±0   4m 5s ⏱️ -1s
1 350 tests ±0  1 346 ✅ ±0   4 💤 ±0  0 ❌ ±0 
7 227 runs  ±0  7 207 ✅ ±0  20 💤 ±0  0 ❌ ±0 

Results for commit f071ae0. ± Comparison against base commit 6b108a7.

This pull request removes 2 and adds 1 tests. Note that renamed tests count towards both.

, 1
com.hedera.pbj.runtime.Utf8ToolsTest ‑ [4] 

com.hedera.pbj.runtime.Utf8ToolsTest ‑ [4] 
, 1

[github-actions]

Integration Test Report

    410 files  +1      410 suites  +1   20m 17s ⏱️ + 3m 52s
114 861 tests +8  114 861 ✅ +8  0 💤 ±0  0 ❌ ±0 
115 102 runs  +8  115 102 ✅ +8  0 💤 ±0  0 ❌ ±0 

Results for commit f071ae0. ± Comparison against base commit 6b108a7.

This pull request removes 3 and adds 11 tests. Note that renamed tests count towards both.

com.hedera.pbj.integration.test.ParserNeverWrapsTest ‑ [1] com.hedera.pbj.integration.test.ParserNeverWrapsTest$$Lambda/0x00007fcf17bbd518@15dbf6f4
com.hedera.pbj.integration.test.ParserNeverWrapsTest ‑ [2] com.hedera.pbj.integration.test.ParserNeverWrapsTest$$Lambda/0x00007fcf17bbd748@493b2893
com.hedera.pbj.integration.test.ParserNeverWrapsTest ‑ [3] com.hedera.pbj.integration.test.ParserNeverWrapsTest$$Lambda/0x00007fcf17bbd978@60e56cf9

com.hedera.pbj.integration.test.ParserNeverWrapsTest ‑ [1] com.hedera.pbj.integration.test.ParserNeverWrapsTest$$Lambda/0x00007f5afbb64a78@793ce65c
com.hedera.pbj.integration.test.ParserNeverWrapsTest ‑ [2] com.hedera.pbj.integration.test.ParserNeverWrapsTest$$Lambda/0x00007f5afbb64ca8@34354757
com.hedera.pbj.integration.test.ParserNeverWrapsTest ‑ [3] com.hedera.pbj.integration.test.ParserNeverWrapsTest$$Lambda/0x00007f5afbb64ed8@24baa7c2
pbj.integ.test.enumeration.reserved.pbj.integration.tests.tests.MessageWithReservedEnumTest ‑ [1] NoToStringWrapper{pbj.integ.test.enumeration.reserved.pbj.integration.tests.MessageWithReservedEnum}
pbj.integ.test.enumeration.reserved.pbj.integration.tests.tests.MessageWithReservedEnumTest ‑ [2] NoToStringWrapper{pbj.integ.test.enumeration.reserved.pbj.integration.tests.MessageWithReservedEnum}
pbj.integ.test.enumeration.reserved.pbj.integration.tests.tests.MessageWithReservedEnumTest ‑ [3] NoToStringWrapper{pbj.integ.test.enumeration.reserved.pbj.integration.tests.MessageWithReservedEnum}
pbj.integ.test.enumeration.reserved.pbj.integration.tests.tests.MessageWithReservedEnumTest ‑ [4] NoToStringWrapper{pbj.integ.test.enumeration.reserved.pbj.integration.tests.MessageWithReservedEnum}
pbj.integ.test.enumeration.reserved.pbj.integration.tests.tests.MessageWithReservedEnumTest ‑ [5] NoToStringWrapper{pbj.integ.test.enumeration.reserved.pbj.integration.tests.MessageWithReservedEnum}
pbj.integ.test.enumeration.reserved.pbj.integration.tests.tests.MessageWithReservedEnumTest ‑ [6] NoToStringWrapper{pbj.integ.test.enumeration.reserved.pbj.integration.tests.MessageWithReservedEnum}
pbj.integ.test.enumeration.reserved.pbj.integration.tests.tests.MessageWithReservedEnumTest ‑ testCodecGetDefaultValueMethod()
…