Copy from built-in documentation with selection starts from line start sometimes copy the upper line

[jsjtxietian]

Tested versions

Godot v4.3.dev (3c59609)

System information

Windows 10.0.19045 - Vulkan (Forward+) - dedicated NVIDIA GeForce RTX 3060 (NVIDIA; 31.0.15.3619) - 11th Gen Intel(R) Core(TM) i7-11700K @ 3.60GHz (16 Threads)

Issue description

When debugging #87463, I did some test myself and found a new issue, keep it seperate because it may have different underlying reasons.

I want to copy If exact_match is false

But instead I got

This is useful for code that needs to run only once when an action is pressed, instead of every frame while it's pressed.

If exact_match is false

In my clipboard

See the video:

_2024_01_22_17_41_42_629.mp4

Steps to reproduce

1. Open built-in doc
2. Copy from line start, and paste and observe.

Minimal reproduction project (MRP)

N/A

[dalexeev]

Most likely this is a RichTextLabel bug. CC @bruvzg