Update the VS Code editor UI if a server-side document was changed during save

[isc-bsaviano]

This PR fixes #1565. Calling the revert command looks a little hacky, but the end result is the same as the version 2.x behavior.

[gjsjohnmurray]

From a quick read of the code I'm not sure if it always uses revert for classes. Even if it does, I don't recall if 2.x worked that way too.

[isc-bsaviano]

You are correct that revert is not always used for classes. It's not used when compilation changes the document because that change will update the mtime a second time. VS Code will see that change and refresh itself automatically without the prodding via revert.

2.x didn't use the same mechanism, but it worked the same way. In 2.x the save was done in an onDidSaveTextDocument handler that ran after the writeFile() and subsequent stat(). In that case, the stat() after writeFile() reported the same mtime as before the write since the file had not been written yet. Then when the write actually happened in the onDidSaveTextDocument handler, VS Code detected that mtime change as not being caused by writeFile() so it updated its UI.

[gjsjohnmurray]

Once merged I will start using the beta and look out for any unexpected changes of behaviour during my everyday server-side editing.

[isc-bsaviano]

Thanks @gjsjohnmurray. I plan on doing a 3.0.3 release by the end of the day next Monday so that leaves plenty of time for beta verification.