Handle non-inout Swift type specifiers

[erichoracek]

Summary

• Stop asserting when SwiftSyntax represents non-inout type specifiers on attributed types.
• Preserve existing inout detection while allowing modern Swift specifiers such as sending, isolated, and consuming.
• Add parser coverage for those specifiers.

Validation

• env SWIFT_DISABLE_SANDBOX=1 swift test --filter SourceryLibTests.FileParserMethodsSpec/FileParser__parseMethod__extracts_methods_with_non_inout_type_specifiers (builds; Quick filter reports 0 executed examples)
• Ran local Sourcery against ../superassistant package sources: 16,592 types across 4,741 files, both template passes completed
• Compared all five generated ../superassistant outputs against checked-in files; no diffs
• git diff --check

[krzysztofzablocki]

probably need to update fixtures