docs: add multi-axis roll examples to documentation

Author: f14XuanLv

docs/source/numpy.rst

@@ -291,6 +291,8 @@ not modify the underlying xexpression.
      - :cpp:func:`xt::rot90\<2\>(a, {1, 2}) <xt::rot90>`
    * - :any:`np.roll(a, 2, axis=1) <numpy.roll>`
      - :cpp:func:`xt::roll(a, 2, 1) <xt::roll>`
+   * - :any:`np.roll(a, (1, 2), axis=(0, 1)) <numpy.roll>`
+     - :cpp:func:`xt::roll(a, {1, 2}, {0, 1}) <xt::roll>`
 
 Iteration
 ---------

docs/source/quickref/manipulation.rst

@@ -64,8 +64,9 @@ roll
     #include <xtensor/misc/xmanipulation.hpp>
 
     xt::xarray<int> a = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};
-    auto t0 = xt::roll(a, 2);
-    auto t1 = xt::roll(a, 2, 1);
+    auto t0 = xt::roll(a, 2);           // roll flattened array
+    auto t1 = xt::roll(a, 2, 1);        // roll along axis 1
+    auto t2 = xt::roll(a, {1, 2}, {0, 1});  // roll along multiple axes
 
 rot90
 -----