Backport changes from #497 and #506 to v0.32 docs (#507)

* Backport changes from #497 to v0.32 docs

Namely, using a single environment for the project. This ensures that
this branch plays well with the GitHub workflow.

* Update README

As per #506

* Streamline instructions for rendering a single file

Author: penelopeysm

.gitignore

@@ -13,12 +13,13 @@
 /tutorials/**/index_files/*
 Testing/
 /*/*/jl_*/
-/Manifest.toml
-/test/Manifest.toml
 .vscode
 _freeze
 _site
 .quarto
 /.quarto/
 changelog.qmd
-versions.qmd
+versions.qmd
+tmp.gif
+.venv
+venv