Bug with incorrectly reporting undefined-global

Personne n'a encore pris cette issue.

So I have this very strange bug where the VSCode extension starts reporting undefined-globals but when I click on the actual problem report, it goes away.

These globals are defined in a file that is loaded as a library via an [extension](https://github.com/Ketho/vscode-wow-api) so I figured I might reach the max workspace files/size limit but even with those set to very high numbers it keeps happening. I can click on all of them to make them go away but the next indexing run (hitting save) will bring them back.

`workspace.maxPreload` is set to `20000`
`workspace.preloadFileSize` is set to `8000`

The repo I tested with is [WeakAuras](https://github.com/WeakAuras/WeakAuras2)

https://user-images.githubusercontent.com/75278/202040021-d15fda8e-85ce-4055-a39e-d9538f6b5446.mp4

So my next guess was that the LSP just crashes and restarts, I checked the output panel and got this:

```
script/core/diagnostics/param-type-mismatch.lua:21: attempt to index a nil value (field 'generic')
stack traceback:
script/core/diagnostics/param-type-mismatch.lua:21: in upvalue 'expandGenerics'
script/core/diagnostics/param-type-mismatch.lua:48: in upvalue 'getDefNode'
script/core/diagnostics/param-type-mismatch.lua:97: in local 'callback'
script/parser/guide.lua:716: in function 'parser.guide.eachSourceType'
script/core/diagnostics/param-type-mismatch.lua:83: in function 'core.diagnostics.param-type-mismatch'
script/core/diagnostics/init.lua:117: in upvalue 'check'
script/core/diagnostics/init.lua:174: in function 'core.diagnostics'
[C]: in function 'xpcall'
script/provider/diagnostic.lua:324: in function 'provider.diagnostic.doDiagnostic'
[C]: in function 'xpcall'
script/provider/diagnostic.lua:665: in upvalue 'callback'
script/files.lua:880: in function
script/core/diagnostics/param-type-mismatch.lua:21: attempt to index a nil value (field 'generic')
```

Reproduisez le problème dans le dépôt WeakAuras avec l’extension VSCode et les paramètres d’espace de travail signalés. Commencez par script/core/diagnostics/param-type-mismatch.lua à la ligne 21 et suivez la pile à travers script/provider/diagnostic.lua ; le travail est terminé lorsque l’indexation des diagnostics ne provoque plus de plantage et que les rapports concernant les variables globales non définies restent corrects après la réindexation.

Rédigé par le modèle d'indexation à partir du texte de l'issue.