Fix backwards character deletion on other whitespaces (#2855)

* delete_backwards_char accepts any type of whitespace

* Fix inconsistency, where unicode whitespaces are treated as normal whitespaces

* Changed back to direct whitespace match

* Only accept explicit whitespace / tabs

Co-authored-by: s0LA1337 <dreamer@neoncity.dev>

helix-term/src/commands.rs

@@ -2948,7 +2948,7 @@ pub fn delete_char_backward(cx: &mut Context) {
                 let line_start_pos = text.line_to_char(range.cursor_line(text));
                 // consider to delete by indent level if all characters before `pos` are indent units.
                 let fragment = Cow::from(text.slice(line_start_pos..pos));
-                if !fragment.is_empty() && fragment.chars().all(|ch| ch.is_whitespace()) {
+                if !fragment.is_empty() && fragment.chars().all(|ch| ch == ' ' || ch == '\t') {
                     if text.get_char(pos.saturating_sub(1)) == Some('\t') {
                         // fast path, delete one char
                         (