Text editor improvements

[Rytelier]

Describe the project you are working on

Code, shaders, database

Describe the problem or limitation you are having in your project

Some text editing task are becoming tedious, like quick cloning lines, renaming objects, selecting multiple items.

Describe the feature / enhancement and how it helps to overcome the problem or limitation

Text editor got good improvements over time, there's more functionality though that would help writing text based resources efficiently.

Describe how your proposal will work, with code, pseudo-code, mock-ups, and/or diagrams

Selection:

• Allow to place multiple cursors by alt+drag mouse. Currently it's only possible by clicking, adding dragging to it would allow to selected a column faster.
• Allow to remove cursors by alt+clicking on already placed ones.

Actions and shortcuts:

• Add shortcut to duplicate selected lines/selected range with ctrl+d.
• Add function to quickly rename object and its references. Different from search-replace as it would detect the object instead of searching for plain matching text.

Support:

• Add support for config files and resources syntax highlighting and correct formatting checks.

If this enhancement will not be used often, can it be worked around with a few lines of script?

Some features could be added in a plugin, some rather not, it would require research.

Is there a reason why this should be core and not an add-on in the asset library?

Text editing is tightly integrated into developing a game and it's helpful to it be as efficient as possible.

[AThousandShips]

Allow to place multiple cursors by alt+drag mouse.

• Tracked in: https://github.com/godotengine/godot-proposals/discussions/7004

[Calinou]

Add function to quickly rename object and its references. Different from search-replace as it would detect the object instead of searching for plain matching text.

• This is already being tracked in https://github.com/godotengine/godot-proposals/issues/899.

Add support for config files and resources syntax highlighting and correct formatting checks.

This is being implemented by https://github.com/godotengine/godot/pull/77972. Note that ConfigFile and TSCN/TRES don't have a style guide though, as these are not expected to be modified by hand.