Option for showing more/all file types in FileSystem dock

[SarahCosmosys]

Godot version:
3.0.6

OS/device including version:
Windows 10

Issue description:
Can't see .cfg files in the file explorer dock

Steps to reproduce:

1. Create a new godot project
2. Make a script that saves a new ConfigFile within the res:// directory
3. Try and look for where you saved in the file explorer dock

[Chaosus]

Well its not only cfg files - txt, exe, dat is not visible too, editor dock is not supposed to be a full system explorer - the idea is to support only specific files extensions which is useful for game development and can be edited in the editor itself

[akien-mga]

Indeed, this is by design, the FileSystem dock only lists files that you can actually use directly (scenes, resources).

Now that the Script editor allows opening arbitrary text files, there could be a use case for seeing files like .cfg or .json in the FileSystem dock. Maybe as an option where you can set a whitelist of file types you want to include in the FileSystem dock.

[PLyczkowski]

IMO the fact that the Godot Editor can't open a file type is not a reason to not show that file type in the FileSystem Dock, and when the user tries to open a file that the editor don't know how to open, it should send it to the default OS application.

Currently, you have to have 2 file explorers active when working on a Godot project, and keep them more or less in sync by hand - one in the Godot Editor, and one that can show files like txt, json, psd, .blend etc.

Also displaying a non-accurate state of directories (with files not displayed) in the editor can cause the user to delete directories with important files, or assume wrongly they are not there.

[SolarLune]

Generally agree; it would be wise, in my opinion, to support additional / all formats (or some kind of whitelist), especially if they're human-readable like txt or json, since not being able to edit or read certain formats limits the usability of the script editor (since it's easier to just jump to a different editor permanently rather than switching constantly).

Note that this is no longer the case, but makes an example - As a use case, I made a scripting language and stored the scripts in files that ended with ".events". The files themselves were just text files, but Godot can't read or open them, so I had to switch to VSCode.

[clayjohn]

Feature and improvement proposals for the Godot Engine are now being discussed and reviewed in a dedicated Godot Improvement Proposals (GIP) (godotengine/godot-proposals) issue tracker. The GIP tracker has a detailed issue template designed so that proposals include all the relevant information to start a productive discussion and help the community assess the validity of the proposal for the engine.

The main (godotengine/godot) tracker is now solely dedicated to bug reports and Pull Requests, enabling contributors to have a better focus on bug fixing work. Therefore, we are now closing all older feature proposals on the main issue tracker.

If you are interested in this feature proposal, please open a new proposal on the GIP tracker following the given issue template (after checking that it doesn't exist already). Be sure to reference this closed issue if it includes any relevant discussion (which you are also encouraged to summarize in the new proposal). Thanks in advance!