Replace TsBuffer.h with std::string_view, ts::TextView or ts::MemSpan

[ywkaras]

Add capabilities missing (if any) to TextView and MemSpan.

[SolidWallOfCode]

ts::TextView is actually a derivative of and intended replacement for ts::ConstBuffer, which is the const version of ts::Buffer, so what happened is features ts::Buffer lacked were added to ts::TextView.

For ts::Buffer itself, that should be replaced with ts::MemSpan, because those are intended for tracking writable memory.

[ywkaras]

OK changed title and description based on your comment.

[bryancall]

This cleanup is complete. Usage of the legacy buffer types was migrated to TextView / MemSpan / std::string_view incrementally, and the now-unused TsBuffer.h was removed in #13281 (merged 2026-06-16). The header is gone from current master with no remaining includes. Closing as done.

Correction: this cleanup (PR #13281) is targeted for the 11.0.0 milestone and has not shipped in a release yet — 10.1.x and 10.2.x still contain TsBuffer.h. It is merged to master only.