Clear cache for any files that reference includes that are changed

[SanjulaGanepola]

Changes

Fixes #465

Whenever include files are changed now, we clear the cache for any files that reference that include.

Before

after making some changes to the ILE Docs in empdet.rpgleinc, the hover is not updated in empdet.sqlrpgle:

After

[SanjulaGanepola]

@worksofliam At a quick glance, is there any issues with clearing the cache in this scenario?

[chrjorgensen]

@SanjulaGanepola Have I understood your change correctly in that you only invalidate the cache for the changed include file and not for all includes? If you can confirm, I will test and review.

I don't see any reason for not clearing the cache for changed includes - on the contrary! Cache programming is one of the hardest programming disciplines, and I think you're absolutely right here.

[SanjulaGanepola]

@chrjorgensen Caching can indeed be tricky.

Just so its clear, here is the updated flow:

1. When a file changes, it triggers onDidChangeContent
2. We call getDocs with ignoreCache: true on this changed file so the cache is updated for this changed file
3. The linter diagnostics are also then refreshed for this changed file
4. We iterate on every file in the parser's cache and check if any of those files include this changed file. If it does find a file, it will remove that file from the cache.

The only part that is new with this PR is step 4.