Historically it was often not quite clear to users what PHP version
Psalm assumes, and why. This PR addresses this issue by printing the
version and where we got it from right before scanning the files.
* Remove file map cache when re-analyzing files
When the project is re-analyzed under the single thread condition (not using a process pool), the filemaps are not cleared before re-analyzing files. This means that file maps only get appended to. If you delete the contents of a file via the LSP, the file map will still be populated with all the old values for example.
In doing this I had to write a few more tests to check my assumptions too, so adding those additional tests.
* Rename test
* Formatting
* Formatting again!