Refactor the use of the editor finder

[jtpio]

Glancing at the code, it looks like the EditorFinder (used to find editors matching the temporary cells) is passed all the way down to the EditorHandler here:

debugger/src/handlers/editor.ts

Line 50 in a056c28

this._editorFinder = options.editorFinder;

And used only once here:

debugger/src/handlers/editor.ts

Lines 163 to 168 in a056c28

	void this._debuggerService.updateBreakpoints(
	this._editor.model.value.text,
	breakpoints,
	this._path,
	this._editorFinder
	);

This makes editor handlers very coupled to the EditorFinder.

Moreover the editor finder is passed to the NotebookHandler here:

debugger/src/handler.ts

Lines 215 to 219 in a056c28

	this._handlers[widget.id] = new NotebookHandler({
	debuggerService: this._service,
	widget: widget as NotebookPanel,
	editorFinder: this._editorFinder
	});

But not to the ConsoleHandler and FileHandler:

debugger/src/handler.ts

Lines 221 to 232 in a056c28

	case 'console':
	this._handlers[widget.id] = new ConsoleHandler({
	debuggerService: this._service,
	widget: widget as ConsolePanel
	});
	break;
	case 'file':
	this._handlers[widget.id] = new FileHandler({
	debuggerService: this._service,
	widget: widget as DocumentWidget<FileEditor>
	});
	break;

Refactoring this should help fix #471 and #414, as a follow-up to #454 (review)

[jtpio]

Another point to refactor is the use of the non-optional focus parameter as mentioned in #454 (comment):

debugger/src/editor-finder.ts

Lines 77 to 81 in a056c28

	find(
	debugSessionPath: string,
	source: string,
	focus: boolean
	): IIterator<CodeEditor.IEditor> {

[KrzysztofSikoraCodete]

Good point. We definitely pass the editor-finder object too deeply.

[jtpio]

Fixed by #474.