settings: Add auto completion to command aliases setting (#54496)

Update the JSON schema generated for the settings file in order to be
able to provide the list of valid actions when editing the values for
the `command_aliases` setting.

While reviewing https://github.com/zed-industries/zed/pull/52892 , I
noticed that, even though we already have support for this in the keymap
file, we don't support it for the `command_aliases` setting, so went
ahead and refactored this a bit such that the existing functionality for
the keymap file JSON schema could also be re-used for the
`command_aliases` setting.

Here's a quick big-picture breakdown of the relevant changes:

* Add `settings_content::ActionName` newtype, representing a simple
named action without arguments. The
`settings_content::ActionName::build_schema` function can be used to
build the schema of all possible action names.
* Add `settings_content::ActionWithArguments` newtype, representing an
action with arguments. This was mostly done so as to keep both action
without arguments and action with arguments newtypes together,
even though we don't have
`settings_content::ActionWithArguments::build_schema`, as it is only
used by the keymap schema generation logic and probably doesn't warrant
moving it here right now.
* Update both
`settings_content::WorkspaceSettingsContent::command_aliases` and
`workspace::workspace_settings::WorkspaceSettings::command_aliases` to
now be of type `HashMap<String, ActionName>` such that, when the json
schema for `command_aliases` is generate, it'll now reference the
`#/$defs/ActionName` schema.
* Update `SettingsStore::json_schema` so as to populate the
`#/$defs/ActionName` schema at runtime, replacing it with the actual
list of valid action names.

Self-Review Checklist:

- [x] I've reviewed my own diff for quality, security, and reliability
- [x] Unsafe blocks (if any) have justifying comments
- [x] The content is consistent with the [UI/UX
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
- [x] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable

Release Notes:

- Added support for auto-completing action names on `command_aliases`
setting

crates/docs_preprocessor/src/main.rs

@@ -3,7 +3,7 @@ use mdbook::BookItem;
 use mdbook::book::{Book, Chapter};
 use mdbook::preprocess::CmdPreprocessor;
 use regex::Regex;
-use settings::{KeymapFile, SettingsStore};
+use settings::{KeymapFile, SettingsJsonSchemaParams, SettingsStore};
 use std::borrow::Cow;
 use std::collections::{HashMap, HashSet};
 use std::io::{self, Read};
@@ -369,7 +369,18 @@ fn find_binding_with_overlay(
 }
 
 fn template_and_validate_json_snippets(book: &mut Book, errors: &mut HashSet<PreprocessorError>) {
-    let settings_schema = SettingsStore::json_schema(&Default::default());
+    let params = SettingsJsonSchemaParams {
+        language_names: &[],
+        font_names: &[],
+        theme_names: &[],
+        icon_theme_names: &[],
+        lsp_adapter_names: &[],
+        action_names: &[],
+        action_documentation: &HashMap::default(),
+        deprecations: &HashMap::default(),
+        deprecation_messages: &HashMap::default(),
+    };
+    let settings_schema = SettingsStore::json_schema(&params);
     let settings_validator = jsonschema::validator_for(&settings_schema)
         .expect("failed to compile settings JSON schema");