Incorrectly excluded directory

A problem I had was that some references remained unresolved by the language server although they were correct.
The problem turned out to be that they were under a `target` directory, which is excluded by the language server, as seen in the following snippet.

https://github.com/fwcd/kotlin-language-server/blob/bc5309964d24053dd80aed193975629c3e8546ca/shared/src/main/kotlin/org/javacs/kt/SourceExclusions.kt#L13

# Solution
I think ideally, the language server should do something more sensible than using the hardcoded exclusion rules and allow customization of that behaviour via options.

But for now, a workaround is to symlink the incorrectly excluded directories to a non-excluded name.
E.g. in my case I used `ln -s target trgt`.

Start with shared/src/main/kotlin/org/javacs/kt/SourceExclusions.kt at the referenced exclusion rule and examine how the language server handles directories such as target. The issue describes customization via options as the desired outcome; done should avoid incorrect exclusions without relying on the symlink workaround.

Written by the indexing model from the issue text.