Erroneous highlighting of "match"

Hi,

Great work with this project!

I noticed that if I use a function named "matchXyz", the word 'match' is highlighted as if it was a keyword.

Please see how this example is highlighted:
```css
service cloud.firestore {
function matchName(name) {
return name === "john";
}

match /databases/{database}/documents {
match /users/{username} {
allow update: if matchName(username);
}
}
}
```
It looks like this with the extension installed:

The "match" on ln 8 should not be highlighted.

Start by reproducing the reported highlighting in the VSCode Firebase extension with the Firestore Security Rules example from the issue. Find the syntax-highlighting entry point for Firestore rules and verify that matchName is not treated as the match keyword, while standalone match expressions remain highlighted. No file or test is named in the report.

Written by the indexing model from the issue text.