All validation errors are shown in the editor, even if they come from other ALE files

[echebbi]

Bug description

Since #115 we can use several .ale source files. However, when a validation error (not a parsing error) is detected in one file, it will always be shown as a marker in the ALE editor, even if the error doesn't originate from the edited file.

Expected behavior

The error marker is only added to the editor when the error actually comes from the edited file.

How to reproduce

Steps to reproduce the behavior:

1. Create a new ALE project
2. Add a new ALE source file (and add it to the environment)
3. Write a semantic error (e.g. self := 12;)
4. Open the other ALE source file

Additional context

• ALE version: master @ 265f946

Screenshot

Errors come from the left file and are reported on the right one as well: