[Docs] Replace recommonmark with MyST parser

We used recommonmark so that we can use markdown in sphinx but it is
buggy and now so switch to better supported MyST-parser.

* Fixed incorrect heading warnings in markdown.
* Added sphinx toctree to markdown using directive as required by MyST.
* Upgraded Sphinx to 4.3

Ref: https://myst-parser.readthedocs.io

1 files changed, 9 insertions, 4 deletions

diff --git a/docs/source/devguide/index.md b/docs/source/devguide/index.md
index bde04b3e0..436a72a11 100644
--- a/docs/source/devguide/index.md
+++ b/docs/source/devguide/index.md
@@ -2,7 +2,12 @@
 
 This is a guide to help with developing Deluge.
 
-- [Tutorials](tutorials/index.md)
-- [How-to guides](how-to/index.md)
-- [Packaging](packaging/index.md)
-- [Changelog](../changelog.md)
+```{toctree}
+:titlesonly:
+
+Tutorials <tutorials/index>
+how-to/index
+Packaging <packaging/index>
+../changelog
+../depends
+```