doc: Add textarea examples (#357)

* chore: bump bubbles@master

* doc(textarea): Add example of `chat` application with textarea

* doc(textarea): Add example of `textarea` prompting the user to tell a story

* doc(textarea): Add example of `split-editors` on how to manage multiple textareas

examples/textarea/main.go

@@ -0,0 +1,82 @@
+package main
+
+// A simple program demonstrating the text input component from the Bubbles
+// component library.
+
+import (
+	"fmt"
+	"log"
+
+	"github.com/charmbracelet/bubbles/textarea"
+	tea "github.com/charmbracelet/bubbletea"
+)
+
+func main() {
+	p := tea.NewProgram(initialModel())
+
+	if err := p.Start(); err != nil {
+		log.Fatal(err)
+	}
+}
+
+type tickMsg struct{}
+type errMsg error
+
+type model struct {
+	textarea textarea.Model
+	err      error
+}
+
+func initialModel() model {
+	ti := textarea.New()
+	ti.Placeholder = "Once upon a time..."
+	ti.Focus()
+
+	return model{
+		textarea: ti,
+		err:      nil,
+	}
+}
+
+func (m model) Init() tea.Cmd {
+	return textarea.Blink
+}
+
+func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
+	var cmds []tea.Cmd
+	var cmd tea.Cmd
+
+	switch msg := msg.(type) {
+	case tea.KeyMsg:
+		switch msg.Type {
+		case tea.KeyEsc:
+			if m.textarea.Focused() {
+				m.textarea.Blur()
+			}
+		case tea.KeyCtrlC:
+			return m, tea.Quit
+		default:
+			if !m.textarea.Focused() {
+				cmd = m.textarea.Focus()
+				cmds = append(cmds, cmd)
+			}
+		}
+
+	// We handle errors just like any other message
+	case errMsg:
+		m.err = msg
+		return m, nil
+	}
+
+	m.textarea, cmd = m.textarea.Update(msg)
+	cmds = append(cmds, cmd)
+	return m, tea.Batch(cmds...)
+}
+
+func (m model) View() string {
+	return fmt.Sprintf(
+		"Tell me a story.\n\n%s\n\n%s",
+		m.textarea.View(),
+		"(ctrl+c to quit)",
+	) + "\n\n"
+}