Generate docs exampels for Python 3.10 and above

[Bobronium]

Change Summary

Embedding examples workflow is simplified:

Current	New
```py {!.tmp_examples/schema_main.py!} ``` _(This script is complete, it should run "as is")_ Outputs: ```json {!.tmp_examples/schema_main.json!} ```	{!.tmp_examples/schema_main.md!}

docs/build/exec_examples.py will now:

1. check if example uses all features of minimal supported version via pyupgrade
2. create and add versions of the file with upgraded syntax that correspond to major python releases, if applicable
3. add This script is complete, it should run "as is" if applicable
4. add json output if applicable

Screenshots

Tabs

Json output, single tab, incomplete script

Related issue number

Closes #4334

Checklist

• Unit tests for the changes exist
• Tests pass on CI and coverage remains at 100%
• Documentation reflects the changes where applicable
• changes/<pull request or issue id>-<github username>.md file added describing change
  (see changes/README.md for details)
• My PR is ready to review, please add a comment including the phrase "please review" to assign reviewers

[Bobronium]

Please review. I mostly need feedback on the approach and end result, rather than detailed review of code/style/etc.
Once I get confirmation that this path is applicable, I'll iron out the implementation and will rerequest full review.

[samuelcolvin]

Without reviewing the code at all, I think the idea is great and the approach is great.

One note, I think I'll change how examples work a lot in V2, see dirty-equals for an example of what I want to do.

That shouldn't affect this, I'll just copy your code or reimplement the same approach when I'm doing the docs for V2.

[Bobronium]

Ok, this should be ready. Plesase review.

I've cleaned up the implementation and allowed multiple future versions to be generated, e.g. Python 3.7, 3.9, 3.10, where it's applicable.

[samuelcolvin]

Overall I think this looks great 🎉, thanks so much.

A few small things, but my only significant suggestion is:

Could we change the default tab is the newest version? It seems this isn't possible directly in mkdocs, so options are:

• reverse options so the newest version comes first - I think this is kind of fine???
• use JS to change tab on page load, a bit 🤮 but might work
• ask mkdocs to add this feature - could be slow

[samuelcolvin]

this comment is import for context, please revert.

Also better to use int to keep the meaning of the example as clear as possible.

[Bobronium]

agreed, but waiting for response in #4339 (comment)

[Bobronium]

Replaced List and Any with HttpUrl and added a comment

[samuelcolvin]

Probably better to revert this, it was slightly clear to the layman.

[Bobronium]

The reason it was changed is that List is removed by pyupgrade in 3.9+, so I added Any that shouldn't be removed in any case. Other option is to revert changes and add # dont-upgrade to the top of the file, but it might be unclear why there's no future versions in this example.

And the third way — rethink the whole example so it would fit both versions without confusion on any of them.

[samuelcolvin]

Yes, I think better to import one of the pydantic types like HttpUrl inside the function?

[Bobronium]

Done!

I also called the function so prints get executed to showcase the error and absence of it.

[samuelcolvin]

please update.

[Bobronium]

Could we change the default tab is the newest version? It seems this isn't possible directly in mkdocs, so options are:

Don't know, but the good thing is that mkdocs will remember preffered tab throught the docs, so maybe it's ok for now?

Please review. CI failed with mypy complaining since it can't find libraries used in docs.

My guess is that since mypy previously was used only on pydantic, which didn't have any hard dependencies, it didn't complain much nor required install anything.

I think mypy should really run in matrix with tests or in its own matrix (perhaps just for diffrenent python versions), since results may vary from installation to installation, but that's for another issue.

So options for now:

1. install docs dependencies for linting
2. add devtools and ansi2htm to linting dependencies
3. don't run mypy on docs
4. # type ignore the thing — this will cause unused type ignore comment errors locally

Suggestions?

[samuelcolvin]

You just need to add new sections to setup.cfg like:

pydantic/setup.cfg

Lines 83 to 84 in 4fb872e

	[mypy-toml]
	ignore_missing_imports = true

Please update.

[Bobronium]

Please review.

[samuelcolvin]

this is really exciting 🎉, thanks so much for the contribution.