Markdown: make a pass over languages that depend on markdown

[bpasero]

Extracted from #77990 there are other languages that - when opened - will drag in all of our languages via the markdown dependency.

[mjbvz]

Known built-in grammars that include text.html.markdown:

• F#
• shellscript

[bpasero]

I think also:

• PHP
•  Perl

Show more loading activity than other languages.

[bpasero]

//cc @alexr00

[mjbvz]

@bpasero Do the php and perl grammars pull in the markdown grammar too? I see that the references a few other languages but not markdown

[bpasero]

@mjbvz I basically just printed which grammars are being loaded here:

vscode/src/vs/workbench/services/textMate/browser/abstractTextMateService.ts

Line 194 in 593c968

readFile: (resource: URI) => this._extensionResourceLoaderService.readExtensionResource(resource)

[mjbvz]

Root cause of all of this is microsoft/vscode-textmate#106

We should investigate just how painful fixing the root cause of this issue would be. A few reasons why:

• Markdown files will still have this issue. MD files are found in a large number of repos.
• Many grammars are effected by the same issue. Markdown is just an extreme case of the problem

[alexr00]

@mjbvz what needs to be done for this?

[mjbvz]

Moving to December. Let's first test to see if these languages trigger the slow loading in the first place. If a language is effected, we can investigate how complicated a fix would be and if it would introduce significant regressions in the grammar

[mjbvz]

Closing this snowplow issue as I'm not sure what action to take. If we see performance issues again, I suggest we look into microsoft/vscode-textmate#106 to address this