Add KeyContextView (#19872)

Release Notes:

- Added `cmd-shift-p debug: Open Key Context View` to help debug custom
key bindings



https://github.com/user-attachments/assets/de273c97-5b27-45aa-9ff1-f943b0ed7dfe

crates/gpui/src/keymap.rs

@@ -75,6 +75,18 @@ impl Keymap {
             .filter(move |binding| binding.action().partial_eq(action))
     }
 
+    /// all bindings for input returns all bindings that might match the input
+    /// (without checking context)
+    pub fn all_bindings_for_input(&self, input: &[Keystroke]) -> Vec<KeyBinding> {
+        self.bindings()
+            .rev()
+            .filter_map(|binding| {
+                binding.match_keystrokes(input).filter(|pending| !pending)?;
+                Some(binding.clone())
+            })
+            .collect()
+    }
+
     /// bindings_for_input returns a list of bindings that match the given input,
     /// and a boolean indicating whether or not more bindings might match if
     /// the input was longer.