[docs] Merge note block in `torch.lu` documentation (#63156)

Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/63156

**Summary**
This commit merges the four successive `Note` blocks that appear in the
documentation for `torch.lu`. Each one only has one line in it, so all
of them have been merged into one block with a bulleted list that
contains the original items.

**Test Plan**
Continuous integration.

*Before*
<img width="888" alt="Captura de Pantalla 2021-08-12 a la(s) 10 48 39 a  m" src="https://user-images.githubusercontent.com/4392003/129244443-b7d1594e-8833-4c20-a911-e1bf7ca88a8d.png">

*After*
<img width="932" alt="Captura de Pantalla 2021-08-12 a la(s) 10 48 46 a  m" src="https://user-images.githubusercontent.com/4392003/129244462-1f39dcdb-90e0-4fd9-a95f-343b0b6be1f1.png">

**Fixes**
This commit fixes #62339.

Test Plan: Imported from OSS

Reviewed By: navahgar, pbelevich

Differential Revision: D30292633

Pulled By: SplitInfinity

fbshipit-source-id: cb9071165629bfe7316b1d2fe952e4354c75d48f

diff --git a/torch/functional.py b/torch/functional.py
index a435f72..8898fc9 100644 (file)
--- a/torch/functional.py
+++ b/torch/functional.py
@@ -1442,27 +1442,21 @@ def _lu_impl(A, pivot=True, get_infos=False, out=None):
     ``True``.
 
     .. note::
-        The pivots returned by the function are 1-indexed. If :attr:`pivot` is ``False``,
-        then the returned pivots is a tensor filled with zeros of the appropriate size.
-
-    .. note::
-        LU factorization with :attr:`pivot` = ``False`` is not available for CPU, and attempting
-        to do so will throw an error. However, LU factorization with :attr:`pivot` = ``False`` is
-        available for CUDA.
-
-    .. note::
-        This function does not check if the factorization was successful or not if
-        :attr:`get_infos` is ``True`` since the status of the factorization is present in the
-        third element of the return tuple.
-
-    .. note::
-        In the case of batches of square matrices with size less or
-        equal to 32 on a CUDA device, the LU factorization is repeated
-        for singular matrices due to the bug in the MAGMA library (see
-        magma issue 13).
-
-    .. note::
-       ``L``, ``U``, and ``P`` can be derived using :func:`torch.lu_unpack`.
+        * The pivots returned by the function are 1-indexed. If :attr:`pivot`
+          is ``False``, then the returned pivots is a tensor filled with
+          zeros of the appropriate size.
+        * LU factorization with :attr:`pivot` = ``False`` is not available
+          for CPU, and attempting to do so will throw an error. However,
+          LU factorization with :attr:`pivot` = ``False`` is available for
+          CUDA.
+        * This function does not check if the factorization was successful
+          or not if :attr:`get_infos` is ``True`` since the status of the
+          factorization is present in the third element of the return tuple.
+        * In the case of batches of square matrices with size less or equal
+          to 32 on a CUDA device, the LU factorization is repeated for
+          singular matrices due to the bug in the MAGMA library
+          (see magma issue 13).
+        * ``L``, ``U``, and ``P`` can be derived using :func:`torch.lu_unpack`.
 
     .. warning::
         The LU factorization does have backward support,