feat(v2/textarea): expose Column(), clarify 0-indexing (#875)

Signed-off-by: Carlos Alexandro Becker <caarlos0@users.noreply.github.com>

textarea/textarea.go

@@ -595,11 +595,16 @@ func (m *Model) LineCount() int {
 	return len(m.value)
 }
 
-// Line returns the row position of the cursor.
+// Line returns the 0-indexed row position of the cursor.
 func (m Model) Line() int {
 	return m.row
 }
 
+// Column returns the 0-indexed column position of the cursor.
+func (m Model) Column() int {
+	return m.col
+}
+
 // ScrollYOffset returns the Y offset (top row) index of the current view, which
 // can be used to calculate the current scroll position.
 func (m Model) ScrollYOffset() int {