Update keymap context binding behavior of > and ! (#34664)

Now ! means "no ancestors matches this", and > means "any descendent"
not "any child".

Updates #34570

Co-authored-by: Ben Kunkle <ben@zed.dev>

Release Notes:

- *Breaking change*. The context predicates in the keymap file now
handle ! and > differently. Before this change ! meant "this node does
not match", now it means "none of these nodes match". Before this change
> meant "child of", now it means "descendent of". We do not expect these
changes to break many keymaps, but they may cause subtle changes for
complex context queries.

---------

Co-authored-by: Ben Kunkle <ben@zed.dev>

crates/language_tools/src/key_context_view.rs

@@ -132,14 +132,7 @@ impl KeyContextView {
     }
 
     fn matches(&self, predicate: &KeyBindingContextPredicate) -> bool {
-        let mut stack = self.context_stack.clone();
-        while !stack.is_empty() {
-            if predicate.eval(&stack) {
-                return true;
-            }
-            stack.pop();
-        }
-        false
+        predicate.depth_of(&self.context_stack).is_some()
     }
 
     fn action_matches(&self, a: &Option<Box<dyn Action>>, b: &dyn Action) -> bool {