Fix null related docs.

Author: Ivorforce

docs/how-to-use/getting_started.rst

@@ -45,7 +45,7 @@ NumDot arrays can be indexed and sliced similarly to godot Arrays, but with more
 
     # Slicing
     print(arr1.get(nd.range(1, 4)))   # Outputs: { 2, 3, 4 }
-    print(arr2.get(null, 1))          # Outputs: { 2, 4, 6 }
+    print(arr2.get(&":", 1))          # Outputs: { 2, 4, 6 }
 
 Common Operations
 -----------------

docs/how-to-use/math_performance.rst

@@ -40,8 +40,8 @@ With vectorization, it would execute much, much faster:
 
     var vectors := nd.stack([1000, 2])
     var prog := nd.divide(nd.arange(1000), 10)
-    vectors.set(nd.sin(prog), null, 0)
-    vectors.set(nd.cos(prog), null, 1)
+    vectors.set(nd.sin(prog), &":", 0)
+    vectors.set(nd.cos(prog), &":", 1)
 
 As a rule of thumb: The fewer calls you make to NumDot, the faster your algorithm executes.
 

docs/how-to-use/numpy-xtensor-numdot.csv

@@ -8,8 +8,8 @@ NumPy;xtensor;NumDot;Notes
 | ``a.get_float(0)``";Create a view, or return an element of the tensor.
 ``a[0] = b``;"| ``xt::view(a, { 0 }) = b``
 | ``a(0) = b`` ";"| ``a.set(b, 0)``";Update a slice of a tensor.
-``a[:]``;``xt::view(a, { xt::all() })``;``a.get(null)``;Select all elements.
-``a[None]``;``xt::view(a, { xt::newaxis() })``;"``a.get(&""newaxis"")``";Insert new axis.
+``a[:]``;``xt::view(a, { xt::all() })``;``a.get(&":")``;Select all elements.
+``a[None]``;``xt::view(a, { xt::newaxis() })``;"``a.get(&""newaxis"")``, ``a.get(null)``";Insert new axis.
 ``a[..., 0]``;``xt::view(a, { xt::ellipsis(), 0 })``;"``a.get(&""..."", 0)``";Ellipsis stands in for all other dimensions.
 ``a[2:]``;``xt::view(a, { 2|_ })``;``a.get(nd.from(2))``;Select elements starting at index 2.
 ``a[:2]``;``xt::view(a, { _|2 })``;``a.get(nd.to(2))``;Select elements ending at index 2.

docs/how-to-use/tensors.rst

@@ -64,7 +64,7 @@ Broadcasting is particularly useful in various scenarios, such as:
     # Applying a filter (row-wise operation)
     var arr6 := nd.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
     var mask := nd.array([1, 0, 1])
-    var filtered := nd.multiply(arr6, mask.get(null, &"newaxis"))
+    var filtered := nd.multiply(arr6, mask.get(&":", null))
     print(filtered)          # Outputs:
                              # {{1, 2, 3}
                              #  {0, 0, 0}