web: bump @codemirror/legacy-modes from 6.3.3 to 6.4.0 in /web

Bumps [@codemirror/legacy-modes](https://github.com/codemirror/legacy-modes) from 6.3.3 to 6.4.0.
- [Changelog](https://github.com/codemirror/legacy-modes/blob/main/CHANGELOG.md)
- [Commits](codemirror/legacy-modes@6.3.3...6.4.0)

---
updated-dependencies:
- dependency-name: "@codemirror/legacy-modes"
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

web/package.json

@@ -34,7 +34,7 @@
         "@codemirror/lang-javascript": "^6.2.2",
         "@codemirror/lang-python": "^6.1.5",
         "@codemirror/lang-xml": "^6.1.0",
-        "@codemirror/legacy-modes": "^6.3.3",
+        "@codemirror/legacy-modes": "^6.4.0",
         "@codemirror/theme-one-dark": "^6.1.2",
         "@formatjs/intl-listformat": "^7.5.5",
         "@fortawesome/fontawesome-free": "^6.5.2",