Update hotkey docs

- Relates #826

spring-shell-docs/modules/ROOT/pages/appendices/tui/viewdev.adoc

@@ -5,6 +5,7 @@
 While a _view_ just need to implement `View` it's usually convenient to just
 use `BoxView` as a parent.
 
+[[register-bindings]]
 == Register Bindings
 
 In an `AbstractView` use variants of _registerKeyBinding_, _registerHotKeyBinding_

spring-shell-docs/modules/ROOT/pages/tui/events/key.adoc

@@ -15,3 +15,7 @@ include::{snippets}/KeyHandlingSnippets.java[tag=sample]
 
 `KeyEvent` is a record containing info about a binding coming out
 from a terminal.
+
+Some views allow you to register hot keys which are processed before
+normal key handling. More about this can be found from
+xref:appendices/tui/viewdev.adoc#register-bindings[Register Bindings].

spring-shell-docs/modules/ROOT/pages/tui/views/menubar.adoc

@@ -14,6 +14,15 @@ Inherits xref:tui/views/box.adoc[].
 └─────────────────────────────┘
 ----
 
+_MenuBarView_ is constructed with instances of _MenuBarItem_. _MenuBarItem_ itself
+takes instances of _MenuItem_. _MenuItem_ can define its style and action.
+_MenuBarItem_ can also define a hot key which is used to active particular menu.
+
+[source, java, indent=0]
+----
+include::{snippets}/MenuBarViewSnippets.java[tag=snippet1]
+----
+
 == Default Bindings
 Default _key bindigs_ are: