[feature] support c-enter/c-s-enter/s-enter

showkey -a display:

• Shift + Enter: ^[[27;2;13~
• Control + Enter: ^[[27;5;13~
• Control + Shift + Enter: ^[[27;6;13~

First, prompt-toolkit miss c-enter, s-enter, ...

Second, Even if I

    @add_key_binding(*["escape", "[27;2;13~"])
    def _(event: KeyPressEvent) -> None:
        print("hi")

It still cannot work.

Weirdly, the following keys can work.

• Alt + Control + Enter
• Alt + Control + Shift + Enter

    @add_key_binding(["escape", *"[27;8;13~"])
    def _(event: KeyPressEvent) ->None:
        print("hi")

Reproduce the reported sequences with showkey -a, then trace prompt-toolkit's key binding and escape-sequence handling for c-enter, s-enter, and c-s-enter. Done means these sequences can be registered with add_key_binding and invoke their handlers, including the forms shown in the issue.