Meta issue: Towards a Lean release

[pimotte]

Blockers for pre-release:

• [Bug] [Lean] Autocompletion mistake #358
• [Bug] [Lean] Autocompletion does not work with subproof bullets waterproof-editor#101
• Add Profile Setup #360
• Include all files needed to build these exercises introduction-to-proof-sheets-lean#1
• [Bug] [Lean] Infoview does not update with error until cursor moves #371
• Attribution Verbose Lean introduction-to-proof-sheets-lean#4
• Manually test .vsix
  • On Windows
  • On Mac
  • On Linux

Low-hanging fruit:

• Highlight code snippets in color themes waterproof-editor#105
• Missing tokens/refactor codemirror-lang-verbose#2
• Improve line numbers #373

Longer term (maybe for full release):

• [Bug] [Lean] Clicking into the file quickly breaks the proof view #374
• [Bug] [Lean?] Useless autocomplete suggestions #376
• Possibly a violation of parsing + parsisting documents involving newlines being investigated by @DikieDick
• [Spike/UX] [Lean] Infoview is a bit bulky #357
• [Request] [Lean] Multi-lingual support #369
• [Request] Signal partial progress in proof waterproof-editor#106
• Proposal: Teacher only blocks #370