Substitute VSCode variables more generally

[Veykril]

No description provided.

[Veykril]

@bors r+

[bors]

📌 Commit ec94760 has been approved by Veykril

It is now in the queue for this repository.

[bors]

⌛ Testing commit ec94760 with merge e86bac9...

[bors]

☀️ Test successful - checks-actions
Approved by: Veykril
Pushing e86bac9 to master...

[Dessix]

@Veykril This seems to have caused a regression in the latest build (v0.4.1379). Due to lack of sourcemaps and not having a local build, I've not yet narrowed down the source beyond its final frame:

2023-01-24 19:10:49.661 [error] Activating extension rust-lang.rust-analyzer failed due to an error:
2023-01-24 19:10:49.661 [error] Error: Unexpected function type in substitution
    at Yr (/home/dessix/.vscode-insiders/extensions/rust-lang.rust-analyzer-0.4.1379-linux-x64/out/main.js:41:5460)
    at Yr (/home/dessix/.vscode-insiders/extensions/rust-lang.rust-analyzer-0.4.1379-linux-x64/out/main.js:41:5420)
    at wa.getOrCreateClient (/home/dessix/.vscode-insiders/extensions/rust-lang.rust-analyzer-0.4.1379-linux-x64/out/main.js:96:2623)
    at wa.start (/home/dessix/.vscode-insiders/extensions/rust-lang.rust-analyzer-0.4.1379-linux-x64/out/main.js:96:2959)
    at V_ (/home/dessix/.vscode-insiders/extensions/rust-lang.rust-analyzer-0.4.1379-linux-x64/out/main.js:100:1948)
    at K_ (/home/dessix/.vscode-insiders/extensions/rust-lang.rust-analyzer-0.4.1379-linux-x64/out/main.js:100:763)

I don't appear to have any variable substitutions in my settings.json, am not on NixOS, and have no variable substitutions or similar syntax in my process environment variables.

[lnicola]

Reported as #14022.