Add search terms for all?, any?, length, and keybindings (#5665)

* Add search terms for `all?`

JavaScript has `Array.every` similar to `all?`

* Add search terms for `any?`

JavaScript has `Array.some` similar to `any?`

* Add search terms for `length`

Count, `len()`, and `size`/`sizeof` in widely-known programming languages are equivalent to `length`

* Add search terms for `keybindings`

Shortcut and hotkey are common synonyms (especially in web and GUI land) for keybindings.

crates/nu-command/src/filters/all.rs

@@ -27,6 +27,10 @@ impl Command for All {
         "Test if every element of the input matches a predicate."
     }
 
+    fn search_terms(&self) -> Vec<&str> {
+        vec!["every"]
+    }
+
     fn examples(&self) -> Vec<Example> {
         vec![
             Example {

crates/nu-command/src/filters/any.rs

@@ -27,6 +27,10 @@ impl Command for Any {
         "Tests if any element of the input matches a predicate."
     }
 
+    fn search_terms(&self) -> Vec<&str> {
+        vec!["some"]
+    }
+
     fn examples(&self) -> Vec<Example> {
         vec![
             Example {

crates/nu-command/src/filters/length.rs

@@ -24,6 +24,10 @@ impl Command for Length {
             .category(Category::Filters)
     }
 
+    fn search_terms(&self) -> Vec<&str> {
+        vec!["count", "len", "size"]
+    }
+
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/platform/reedline_commands/keybindings.rs

@@ -21,6 +21,10 @@ impl Command for Keybindings {
         "Keybindings related commands"
     }
 
+    fn search_terms(&self) -> Vec<&str> {
+        vec!["shortcut", "hotkey"]
+    }
+
     fn run(
         &self,
         engine_state: &EngineState,