Fix Backspace deleting entire previous line in `<textarea>` (#36112)

* test(textinput): Add test for backspace at beginning of line in textarea

Introduce a test to reproduce and verify the fix for backspacing at the
beginning of a line in a multiline textarea. This ensures that pressing
Backspace when the cursor is at the start of a line correctly removes the
newline without deleting the entire previous line’s content.

Related to: #27523

Signed-off-by: Emmanuel Elom <elomemmanuel007@gmail.com>

* fix(textinput): Preserve selection origin when adjusting vertical position

Fixes an issue where pressing Backspace at the beginning of a line in a
textarea incorrectly deleted the entire previous line's content. This happened
because `self.adjust_vertical(-1, select)` modified `selection_origin` and
`edit_point`, but `selection_origin` was not restored before performing the
horizontal adjustment. As a result, `self.selection_start()` and
`self.selection_end()` were inconsistent, leading to `replace_operation`
erasing the entire line.

Now, we temporarily store `selection_origin` before adjusting vertical
position and restore it afterward to ensure proper cursor and selection
behavior.

Fixes: #27523
Signed-off-by: Emmanuel Elom <elomemmanuel007@gmail.com>

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Signed-off-by: Emmanuel Elom <elomemmanuel007@gmail.com>
Co-authored-by: Josh Matthews <josh@joshmatthews.net>

0 files changed, 0 insertions, 0 deletions