fix: panicked at 'attempt to subtract with overflow'

helix-term/src/ui/editor.rs:275:29
This would happen when the window-size was to small to display the entire width and one would start jumping forwards with f<some_char> and the beginning of the highlighted area would end up outside of the window

helix-term/src/ui/editor.rs

@@ -272,7 +272,7 @@ impl EditorView {
                             viewport.x + start.col as u16,
                             viewport.y + start.row as u16,
                             // text.line(view.first_line).len_chars() as u16 - start.col as u16,
-                            viewport.width - start.col as u16,
+                            viewport.width.saturating_sub(start.col as u16),
                             1,
                         ),
                         selection_style,