segregate PR CI and dev environment descriptions of nox etc.

Contributing.md

@@ -18,6 +18,7 @@ The following sections also contain specific ideas on where to start contributin
 ## Setting up a development environment
 
 To work and develop PyO3, you need Python & Rust installed on your system.
+
 * We encourage the use of [rustup](https://rustup.rs/) to be able to select and choose specific toolchains based on the project.
 * [Pyenv](https://github.com/pyenv/pyenv) is also highly recommended for being able to choose a specific Python version.
 * [virtualenv](https://virtualenv.pypa.io/en/latest/) can also be used with or without Pyenv to use specific installed Python versions.
@@ -42,9 +43,21 @@ The main nox commands we have implemented are:
 * `nox -s codspeed` will run our suite of rust and python performance tests
 * `nox -s coverage` will analyse test coverage and output `coverage.json` (alternatively: `nox -s coverage lcov` outputs `lcov.info`)
 
+Use  `nox -l` to list the full set of subcommands you can run.
+
+#### UI Tests
+
+PyO3 uses [`trybuild`][trybuild] to develop UI tests to capture error messages from the Rust compiler for some of the macro functionality.
+
+Because there are several feature combinations for these UI tests, when updating them all (e.g. for a new Rust compiler version) it may be helpful to use the `update-ui-tests` nox session:
+
+```bash
+nox -s update-ui-tests
+```
+
 ### Github workflow
 
-In addition to the larger CI workflow which runs on each Pull Request, we provide a short CI workflow which runs on every push to github. This workflow runs the nox sessions: `fustfmt`, `ruff`, `clippy` and `test-rust -- skip-full` and is designed to run in under 200s to provide feedback within a reasonable timeframe and not use all your github actions minutes.
+In addition to the larger CI workflow which runs on each Pull Request, we provide a short CI workflow which runs on every push to github. This workflow runs the nox sessions: `rustfmt`, `ruff`, `clippy` and `test-rust -- skip-full` and is designed to run in under 200s to provide feedback within a reasonable timeframe and not use all your github actions minutes.
 
 ## Ways to help
 
@@ -119,36 +132,21 @@ Tests run with all supported Python versions with the latest stable Rust compile
 
 If you are adding a new feature, you should add it to the `full` feature in our *Cargo.toml** so that it is tested in CI.
 
-You can run these tests yourself with
-`nox`. Use  `nox -l` to list the full set of subcommands you can run.
-
-#### Linting Python code
-`nox -s ruff`
+You can run these tests yourself with `nox`. The full set of actions run in CI is:
 
-#### Linting Rust code
-`nox -s rustfmt`
+1. `nox -s rustfmt` - everything will abort if fmt has not been run on the code before pushing
+1. `cargo semver-checks check-release` (checks no semver violations based on currently released version of Pyo3)
+1. `nox -s set-minimal-package-versions` & `nox -s check-all`
+1. `nox -s clippy-all` on a matrix of different OS, python and rust architectures
+1. build and test against a matrix of different OS, python and rust architectures
+1. test under valgrind to identify memory leakages
+1. `nox -s coverage` for latest windows, macos and ubuntu
+1. `nox -s test` with a debug build of python
+1. `nox -s test-version-limits`
+1. `nox -s check-feature-powerset` to check conditional compilation
+1. cross-compilation tests
 
-#### Semver checks
-`cargo semver-checks check-release`
-
-#### Clippy
-`nox -s clippy-all`
-
-#### Tests
-`cargo test --features full`
-
-#### Check all conditional compilation
-`nox -s check-feature-powerset`
-
-#### UI Tests
-
-PyO3 uses [`trybuild`][trybuild] to develop UI tests to capture error messages from the Rust compiler for some of the macro functionality.
-
-Because there are several feature combinations for these UI tests, when updating them all (e.g. for a new Rust compiler version) it may be helpful to use the `update-ui-tests` nox session:
-
-```bash
-nox -s update-ui-tests
-```
+If you wish to validate your code against this suite before raising a PR, then you can manually trigger the CI in github actions.
 
 ### Documenting changes
 
@@ -263,4 +261,5 @@ In the meanwhile, some of our maintainers have personal GitHub sponsorship pages
 [mdbook]: https://rust-lang.github.io/mdBook/cli/index.html
 [lychee]: https://github.com/lycheeverse/lychee
 [nox]: https://github.com/theacodes/nox
-[pipx]: https://pipx.pypa.io/stable/
+[pipx]: https://pipx.pypa.io/stable/
+[trybuild]: https://github.com/dtolnay/trybuild