allow scrolling past virtual text line

Virtual text lines (either caused by softwrapped inlay hints that take
multiple or line annotations) currently block scrolling downwards.

if the visual offset passed to char_idx_at_visual_offset or
visual_offset_from_block is within a virtual text line then the char
position before the virtual text and a visual offset are returned.
We previously ignored that visual offset and as a result the cursor
would be stuck at the start of the virtual text. This commit fixes
that by simply moving the cursor to the next char (so past the virtual
text) if this visual offset is non-zero

helix-term/src/commands.rs

@@ -1489,18 +1489,19 @@ pub fn scroll(cx: &mut Context, offset: usize, direction: Direction) {
         &annotations,
     );
 
-    let head;
+    let mut head;
     match direction {
         Forward => {
-            head = char_idx_at_visual_offset(
+            let off;
+            (head, off) = char_idx_at_visual_offset(
                 doc_text,
                 view.offset.anchor,
                 (view.offset.vertical_offset + scrolloff) as isize,
                 0,
                 &text_fmt,
                 &annotations,
-            )
-            .0;
+            );
+            head += (off != 0) as usize;
             if head <= cursor {
                 return;
             }