docs(layout): document the difference in the split methods (#750)

* docs(layout): document the difference in the split methods

* fix: doc suggestion

src/layout/layout.rs

@@ -378,6 +378,11 @@ impl Layout {
     /// LruCache, and grows until [`Self::DEFAULT_CACHE_SIZE`] is reached by default, if the cache
     /// is initialized with the [Layout::init_cache()] grows until the initialized cache size.
     ///
+    /// There is a helper method on Rect that can be used to split the whole area into smaller ones
+    /// based on the layout: [`Rect::split()`]. That method is a shortcut for calling this method.
+    /// It allows you to destructure the result directly into variables, which is useful when you
+    /// know at compile time the number of areas that will be created.
+    ///
     /// # Examples
     ///
     /// ```

src/layout/rect.rs

@@ -173,6 +173,9 @@ impl Rect {
     /// An ergonomic wrapper around [`Layout::split`] that returns an array of `Rect`s instead of
     /// `Rc<[Rect]>`.
     ///
+    /// This method requires the number of constraints to be known at compile time. If you don't
+    /// know the number of constraints at compile time, use [`Layout::split`] instead.
+    ///
     /// # Panics
     ///
     /// Panics if the number of constraints is not equal to the length of the returned array.
@@ -185,6 +188,8 @@ impl Rect {
     /// let area = frame.size();
     /// let layout = Layout::vertical([Constraint::Length(1), Constraint::Min(0)]);
     /// let [top, main] = area.split(&layout);
+    /// // or explicitly specify the number of constraints:
+    /// let rects = area.split::<2>(&layout);
     /// # }
     pub fn split<const N: usize>(self, layout: &Layout) -> [Rect; N] {
         layout