Tweak the script editor's line/column indicator for readability

- Use a colon instead of parentheses and a comma to reduce visual
  clutter.
- Pad the line number with 4 spaces to account for scripts longer
  than 999 lines.

(cherry picked from commit 1e8976fcb5)

editor/code_editor.cpp

@@ -803,11 +803,9 @@ void CodeTextEditor::_line_col_changed() {
 	}
 
 	StringBuilder sb;
-	sb.append("(");
-	sb.append(itos(text_editor->cursor_get_line() + 1).lpad(3));
-	sb.append(",");
+	sb.append(itos(text_editor->cursor_get_line() + 1).lpad(4));
+	sb.append(" : ");
 	sb.append(itos(positional_column + 1).lpad(3));
-	sb.append(")");
 
 	line_and_col_txt->set_text(sb.as_string());
 }