Load all key bindings that parse and use markdown in error notifications (#23113)

* Collects and reports all parse errors

* Shares parsed `KeyBindingContextPredicate` among the actions.

* Updates gpui keybinding and action parsing to return structured
errors.

* Renames "block" to "section" to match the docs, as types like
`KeymapSection` are shown in `json-language-server` hovers.

* Removes wrapping of `context` and `use_key_equivalents` fields so that
`json-language-server` auto-inserts `""` and `false` instead of `null`.

* Updates `add_to_cx` to take `&self`, so that the user keymap doesn't
get unnecessarily cloned.

In retrospect I wish I'd just switched to using TreeSitter to do the
parsing and provide proper diagnostics. This is tracked in #23333

Release Notes:

- Improved handling of errors within the user keymap file. Parse errors
within context, keystrokes, or actions no longer prevent loading the key
bindings that do parse.

crates/command_palette/src/command_palette.rs

@@ -15,7 +15,6 @@ use gpui::{
     ParentElement, Render, Styled, Task, UpdateGlobal, View, ViewContext, VisualContext, WeakView,
 };
 use picker::{Picker, PickerDelegate};
-
 use postage::{sink::Sink, stream::Stream};
 use settings::Settings;
 use ui::{h_flex, prelude::*, v_flex, HighlightedLabel, KeyBinding, ListItem, ListItemSpacing};
@@ -635,7 +634,7 @@ mod tests {
             workspace::init(app_state.clone(), cx);
             init(cx);
             Project::init_settings(cx);
-            KeymapFile::parse(
+            cx.bind_keys(KeymapFile::load_panic_on_failure(
                 r#"[
                     {
                         "bindings": {
@@ -645,10 +644,8 @@ mod tests {
                         }
                     }
                 ]"#,
-            )
-            .unwrap()
-            .add_to_cx(cx)
-            .unwrap();
+                cx,
+            ));
             app_state
         })
     }