Fixes#5203
This PR changes behavior when `text/applyChange` returned error.
Before we always assumed that the change was _not_ applied, and tried to send full synchronization still assuming old file content. But this was not the case on some errors (timeouts for example). Now we instead reopen the file (getting its actual content) and then make a full invalidation.
Also added a shortcut allowing manual file reloading, what may be useful in some kinds of error (and also allowed me testing of reopening file in the application).
# Important Notes
The unit tests of sending text updates were improved: now we actually check if all expected messages are emitted from the IDE.
Fixes#6377: The fact that `ctrl-r` was restoring the project to potentially the initial state was confusing. This PR changes that shortcut to `ctrl-shift-r`, as discussed in #6377.
Note that:
- `ctrl-shift-r` was already taken by the re-execution shortcut, so that got the `ctrl-alt` modifiers instead, along with the interruption shortcut for consistency.
- `ctrl-alt-shift-r` was already taken by a shortcut to refresh the whole Electron app, so that wasn't available.
Integrate the UI for electing the Execution Environment with the Language Server and unify existing uses. Implements #5930 + actual integration instead of just mocking it.
https://user-images.githubusercontent.com/1428930/232919438-6e1e295a-34fe-4756-86a4-5f5d8f718fa0.mp4
# Important Notes
The console output is only emitted as part of the `INFO` level. A better check would be to look at the messages sent to the backend in the developer console.
