TextEdit: Correct typo that broke custom selected font color

[GlaceGwyneth]

text_edit's cache was trying to get "font_selected_color" but the colors name as defined in default_theme.cpp is "font_color_selected"
Fixes #27760.

[YeldhamDev]

Try to use the word fix/fixes/close/closes/resolve/resolves before a issue number so it's tagged automatically for closing when the commit is merged.

[akien-mga]

Looks good, but there are some more occurrences of trying to set "font_selected_color" which should be fixed too:

$ rg font_selected
scene/gui/text_edit.cpp
1181:                                                           drawer.draw_char(ci, Point2i(char_ofs + char_margin + ofs_x, yofs + ascent), '_', str[j + 1], in_selection && override_selected_font_color ? cache.font_selected_color : color);
1189:                                                           drawer.draw_char(ci, Point2i(char_ofs + char_margin + ofs_x, yofs + ascent), '_', str[j + 1], in_selection && override_selected_font_color ? cache.font_selected_color : color);
1261:                                                   int w = drawer.draw_char(ci, Point2i(char_ofs + char_margin + ofs_x, yofs + ascent), str[j], str[j + 1], in_selection && override_selected_font_color ? cache.font_selected_color : color);
1268:                                                           draw_rect(Rect2(char_ofs + char_margin + ofs_x, yofs + ascent + 2, w, line_width), in_selection && override_selected_font_color ? cache.font_selected_color : color);
1272:                                                   cache.tab_icon->draw(ci, Point2(char_ofs + char_margin + ofs_x, ofs_y + yofs), in_selection && override_selected_font_color ? cache.font_selected_color : color);
1277:                                                   cache.space_icon->draw(ci, Point2(char_ofs + char_margin + ofs_x, ofs_y + yofs), in_selection && override_selected_font_color ? cache.font_selected_color : color);
4557:   cache.font_selected_color = get_color("font_selected_color");

scene/gui/text_edit.h
187:            Color font_selected_color;

editor/plugins/text_editor.cpp
119:    text_edit->add_color_override("font_selected_color", text_selected_color);

editor/plugins/shader_editor_plugin.cpp
127:    get_text_edit()->add_color_override("font_selected_color", text_selected_color);

editor/plugins/script_text_editor.cpp
240:    text_edit->add_color_override("font_selected_color", text_selected_color);

I would suggest to also rename the variables used internally like text_selected_color and cache.font_selected_color to text_color_selected and cache.font_color_selected to avoid the confusion and further errors.

[GlaceGwyneth]

I decided not to change text_selected_color because that really is the name of the setting.
Its really just font_color_selected that strangely doesn't end with _color like everything else.
Maybe font_color_selected should be the one changing? What do you think?

[akien-mga]

Its really just font_color_selected that strangely doesn't end with _color like everything else.
Maybe font_color_selected should be the one changing? What do you think?

Ideally yes, but that would break compatibility with themes made with earlier Godot version, so it can't be done now. We can rename it in 4.0 though, I'll add a mention to it in #16863.

Changes look good, could you squash commits together?

[akien-mga]

Thanks, and congrats for your first Godot PR :)

[akien-mga]

Cherry-picked for 3.1.2.