feat(keymap): bind Ctrl+Backspace/Ctrl+Delete to word deletion

Add the de-facto standard terminal/editor hotkeys to the default key map:
- Ctrl+Backspace -> delete_word
- Ctrl+Delete -> delete_next_word

Previously only Alt+Backspace/Ctrl+w and Alt+Delete/Alt+d were bound,
which conflicts with muscle memory from readline, VS Code and other TUIs.

Cargo.toml

@@ -3,7 +3,7 @@ name = "tui-textarea-2"
 homepage = "https://github.com/srothgan/tui-textarea#readme"
 repository = "https://github.com/srothgan/tui-textarea"
 documentation = "https://docs.rs/tui-textarea-2/latest/tui_textarea/"
-version = "0.12.1"
+version = "0.12.2"
 edition = "2024"
 rust-version = "1.88.0" # for Ratatui 0.30 split crates
 authors = ["Simon Peter Rothgang <simonrothgang@icloud.com>", "rhysd <lin90162@yahoo.co.jp>"]