Bump to version: v4.34.0

Version bump

This issue is a tracker issue for bumping Physlib to new versions of Lean.
The checklist below should be used to ensure that the bump is done correctly.

Basics

• Update mathlib rev in lakefile.toml.
• Update doc-gen4 rev in lakefile.toml.
• Remove the .lake file, e.g. on unix run rm -rf .lake.
• Run lake update.
• Check lean-toolchain updates correctly.
• Update the Lean version badge in the README.md file.

Build

• Run lake build and fix any errors.

Scripts

• Ensure lake exe lint_all runs without errors.
• Ensure lake exe TODO_to_yml mkFile runs without errors.
• Ensure lake exe stats mkHTML runs without errors.
• Ensure lake exe informal mkFile mkDot mkHTML runs without errors.
• Ensure lake exe make_tag runs without errors.
• Remove the created files rm ./docs/Informal.md; rm ./docs/InformalDot.dot; rm ./docs/InformalGraph.html; rm ./docs/Stats.html; rm ./docs/_data/TODO.yml.

Afterwards

• Create a tag for the new version.
• Put a bump notice on this thread.

Example past bumps

v4.20.0,
v4.20.0-rc5
v4.27.0

Start with lakefile.toml, lean-toolchain, and README.md, following the checklist to update the mathlib and doc-gen4 revisions and regenerate the environment with lake update. Run lake build and each listed lake executable to identify and fix compatibility errors. Done means all checks pass, generated files are removed, the new tag is created, and the bump notice is posted.