Double/triple click in LineEdit not working as expected

[asmaloney]

Godot version:

3.2 branch (f15f5b4)

OS/device including version:

macOS 10.14.6

Issue description:

When double-clicking in a LineEdit, I would expect it to select by word. Instead it selects the entire contents of the LineEdit. I would expect triple click to select the entire contents. (This is the way applications on macOS generally work as well.)

TextEdit and the script editor work properly - line edits are not consistent with them which is confusing (and frustrating).

Steps to reproduce:

1. Select any node with an exported var that shows up as a line edit in the inspector.
2. Change the contents to "Foo bar blat".
3. Double-click on "bar" == the entire contents are selected instead of just "bar".

[Calinou]

I can confirm this on commit ecf432a (3.2 branch) on Linux.

Minimal reproduction project: test_line_edit.zip

simplescreenrecorder-2021-02-20_19.03.33.mp4