Script Window: Attempt to match editor's syntax highlighting

If there is at least one script open in the editor, we can steal its syntax
highlighter and apply it to the script window's CodeEdit control.

Otherwise, we continue to use a built-in SyntaxHighlighter.

Author: wjt

addons/block_code/ui/script_window/script_window.gd

@@ -6,7 +6,20 @@ var script_content: String = ""
 @onready var script_label: CodeEdit = %Code
 
 
+## Attempts to match the syntax highlighting for some open script in the
+## editor, which is more likely to be appropriate for the editor theme
+## than our hardcoded default
+func _apply_editor_syntax_highlighter():
+	var script_editor: ScriptEditor = EditorInterface.get_script_editor()
+	for x in script_editor.get_open_script_editors():
+		var control: Control = x.get_base_editor()
+		if control is TextEdit:
+			script_label.syntax_highlighter = control.syntax_highlighter
+			break
+
+
 func _ready():
+	_apply_editor_syntax_highlighter()
 	script_label.text = script_content.replace("\t", "    ")