[NTG-context] Wiki update: create a .vsix extension package for VisualStudio Code (or VSCodium)

Hello list, I just added some instructions to the WIKI to build an extension file for VSCode, starting from the code you find in the LMTX installation at tex/texmf-context/context/data/vscode/extensions/context You find them at https://wiki.contextgarden.net/VSCode Massi