Add keyboard layout enumeration / set / get functions (macOS, Windows, Linux/X11), remove latin variant function.

Fix whole word search slowdown in editor

Reduce repeated iteration through the full text
when counting the number of occurrences of whole
words while searching a file in the editor.

Fix custom types in node list search

Simplify some code in platform/uwp/export

Add GLTF light import

Co-authored-by: K.S. Ernest (iFire) Lee <ernest.lee@chibifire.com>

Follow-up to #39261.

(cherry picked from commit d68e631566e953e09e71438558b9f1376648d025)

Fix overflow condition with QueryPerformanceCounter

Fix for Expression class: string inside an expression can't be single quoted

Enable zero padding with float specifier for format strings

Make text deletion methods public for LineEdit

Added a "title" attribute for the link tag in the docs xml

Adds full description for AudioEffectRecord.xml.

Enable Unicode support for RegEx class

Account for file deletion and renaming in Export Presets

Build PCRE2 thirdparty library with unicode support. RegEx objects
in Godot can now be used to recognize unicode strings.

Fix custom property editor layout

Ensure that presets are updated with the latest files when
starting up or opening the Project Export dialog. Fixes the
error where Godot would attempt to export deleted files that
were previously selected.

Fix potential crash when listing leaked objects

Note:
Casting to the C++ classes and calling the methods there would work as well,
but would require including he header files for the specific object types handled
here, which wouldn't be OK either.

Improve the 3D light documentations

SCons: Dump construction environment to a file

A new `methods.dump(env)` is added to dump the construction environment
used by SCons to build Godot to a `.scons_env.json`. The file can be used
for debugging purposes and any external tool.

Document the requirement to update the class reference when contributing

See https://github.com/godotengine/godot-docs/issues/3670.

Tree: Calling update in _gui_input less frequently

Fix signal duplication bug when duplicating node with instanced children

AStar: Make get_closest_point() deterministic for equidistant points

doc: Make File store/get integer methods clearer

Fix crash when creating new text file with no name

Fix scene tree showing up when the root selection is present