Serokell Grant 2 Milestone 3

[heitor-lassarote]

This PR contains changes related to Serokell's second grant, third milestone.

Related PRs:

• Serokell Grant 2 Milestone 3 node-motoko#153
• Serokell Grant 2 Milestone 3 vscode-motoko#414

[crusso]

Sorry, I've lost the plot a little bit. What is this actually implementing? Can you provide a link to the milestone description (can be via slack too)?

[heitor-lassarote]

Sorry, I've lost the plot a little bit. What is this actually implementing? Can you provide a link to the milestone description (can be via slack too)?

Here is the grant proposal: https://serokell.notion.site/Motoko-Visual-Studio-Code-Improvements-Proposal-of-Grant-2-1fb6c9c166b380c1bcfefca79b0bb3f8

This PR is specifically about "Improve typer recovery". We are enabling it for the language server, and also allowing IDs to recover from syntax errors.

[alexd1971]

Sorry, I've lost the plot a little bit. What is this actually implementing? Can you provide a link to the milestone description (can be via slack too)?

The commit message should make it clearer:

Problem: The type checker should be more lenient and continue
accumulating typing errors, and try to produce the typed AST even with
errors.

Solution: Use optional parameter `allow_error` in function
`with_message_store`. Provide `enable_type_recovery` flag to flexibly
switch on and off this functionality.