Use Positron's statement range provider for Python docs, when available

[juliasilge]

Addresses posit-dev/positron#1646

You'll notice this is the first time these files have been edited since the formatting was added to this repo; I vote for just muddling through the unrelated formatting changes, if that's OK.

There are two changes needed to get quarto.runCurrent to work as we want it to in a Python .qmd:

• Before this PR, that command resolved to the command for "run cell" so we need to not do that anymore, since this is a situation where we can identify a statement to run.
• When I worked on Add executeSelection method to the extension host cell executor #436, I did not correctly use unadjustedRange() on the way back out of the statement range provider, because R doesn't have anything injected. Turns out that Python does:

quarto/apps/vscode/src/vdoc/languages.ts

Line 43 in 2549e52

inject: ["# type: ignore", "# flake8: noqa"],

[juliasilge]

You can get the .vsix from here to test this out, and what you'll see is that Cmd+Enter now steps through single lines in a Python .qmd, like it has for a while for R. There are some slight differences in behavior between R and Python when you are at the end of a chunk, which we could address with posit-dev/positron#3233.

[cscheid]

👍