HTML5: OS.get_locale() uses hyphens instead of underscores

[pattlebass]

Godot version

v3.5.beta.custom_build [6d9cbcb]

System information

Windows 10, Chrome 103

Issue description

According to the docs, OS.get_locale() should return a string of the form language_Script_COUNTRY_VARIANT@extra (notice the underscores). This isn't the case in HTML5 exports, where it returns a string that uses hyphens.
This also breaks OS.get_locale_language() because it expects underscores.

Windows:

print(OS.get_locale()) # en_US
print(OS.get_locale_language()) # en

HTML5:

print(OS.get_locale()) # en-US
print(OS.get_locale_language()) # en-

It seems that adding locale = locale.replace("-", "_") here solves the issue.
If this fix is good I can open a PR.

Steps to reproduce

See above.

Minimal reproduction project

No response

[Calinou]

Related to #40703.

cc @bruvzg

[bruvzg]

It seems that adding locale = locale.replace("-", "_") here solves the issue.
If this fix is good I can open a PR.

This is a good fix, we do the same for macOS / iOS and Windows.