[Docs] Update Ruby and docs dependencies to the latest versions

[alexandrnikitin]

This PR updates Ruby and docs dependencies to the latest versions. It also fixes some formatting issues in the docs. No visible difference with the current website.

Notes:

• Some dependencies do not support latest (3.3 atm) Ruby version, so it's 3.2 so far.
• Removes ruby_dep gem, not sure why it's needed.
• Removes ruby from Gemlock's platforms, not sure what it is 😊 Tested on Windows using WSL.
• Latest Jekyll doesn't highlight blocks with indentation, so explicit backquotes are needed.
• This PR also replaces tabs with spaces to improve formatting, see screenshot below

Screenshot

[dtchepak]

Thanks @alexandrnikitin ! 🙇

Does the build still fail if the docs have an incorrect code snippet? If so then it is all set to merge 🎉

[alexandrnikitin]

@dtchepak fixed the build. All is green now. Merging.