docs: remove stale API binding and fix MTK compiler typos

[ChrisRackauckas-Claude]

What changed

This PR consolidates the small MTK documentation cleanup needed to keep the docs build and spelling checks green:

• removes the stale non-public ModelingToolkitBase.jacobian_sparsity and ModelingToolkitBase.hessian_sparsity entries from the code-generation API page;
• adds the intentional Comput = "Comput" spelling allowlist entry;
• fixes the mtkcompile documentation typos;
• fixes the analysis_points.jl comment typo.

This supersedes ModelingToolkit #5002, which contained the stale-binding removal alone. No source behavior or public API was changed.

Verification

• typos --format brief .typos.toml docs/src/internals/mtkcompile.md lib/ModelingToolkitBase/test/analysis_points.jl
  • passed
• git diff --check
  • passed
• Runic and the repository CI checks passed on the equivalent individual commits before stacking.
• The branch was force-updated only after verifying the prior remote head 659732fa5984e5281881cff6a35394560674f399.

Please ignore this draft until reviewed by @ChrisRackauckas.