File changes are out of sync with language server

### Description

1. Changes to files don't trigger a change from the language server until they are reopened.
2. Once reopened, the language server uses the previous version of the file, not the latest.

### Extension version
v0.2.24

### Additional context

Screen capture from making changes to _settings.kts_ in the [tekumara/teamcity-kotlin-example](https://github.com/tekumara/teamcity-kotlin-example) repo:

1. The change from `script` -> `script1` is not picked up until _settings.kts_ is reopened
2. Once reopened, a new change from `script1` -> `script` is made. Now the language server is showing the error as if the file still contained `script`.


Start by reproducing the language-server behavior with settings.kts in the linked teamcity-kotlin-example repository using extension v0.2.24. Trace the VS Code extension's file-change handling and language-server synchronization; done means edits trigger updates without reopening and diagnostics use the latest file contents.

Written by the indexing model from the issue text.