Dask master -> main (#4569)

Author: jsignell

docs/release-procedure.md

@@ -1,3 +1,3 @@
 Distributed follows a similar procedure for releasing as the core Dask project.
 
-See https://github.com/dask/dask/blob/master/docs/release-procedure.md for instructions.
+See https://github.com/dask/dask/blob/main/docs/release-procedure.md for instructions.

docs/source/priority.rst

@@ -69,7 +69,7 @@ Dask uses the following priorities, in order:
 3.  **Graph Structure**: Within any given computation (a compute or persist
     call) Dask orders tasks in such a way as to minimize the memory-footprint
     of the computation.  This is discussed in more depth in the
-    `task ordering documentation <https://github.com/dask/dask/blob/master/dask/order.py>`_.
+    `task ordering documentation <https://github.com/dask/dask/blob/main/dask/order.py>`_.
 
 If multiple tasks each have exactly the same priorities outlined above, then
 the order in which tasks arrive at a worker, in a last in first out manner,

docs/source/scheduling-policies.rst

@@ -78,7 +78,7 @@ can be used to break ties and helps us to prioritize nodes with longer critical
 paths and nodes with many children.  The actual algorithms used are somewhat
 more complex and are described in detail in `dask/order.py`_
 
-.. _`dask/order.py`: https://github.com/dask/dask/blob/master/dask/order.py
+.. _`dask/order.py`: https://github.com/dask/dask/blob/main/dask/order.py
 
 Initial Task Placement
 ~~~~~~~~~~~~~~~~~~~~~~
@@ -122,7 +122,7 @@ scheduler, and workers at various points in the computation.
     computing deeply before broadly, preferring critical paths, preferring
     nodes with many dependencies, etc..  This is the same logic used by the
     single-machine scheduler and lives in `dask/order.py
-    <https://github.com/dask/dask/blob/master/dask/order.py>`_.
+    <https://github.com/dask/dask/blob/main/dask/order.py>`_.
 2.  When the graph reaches the scheduler the scheduler changes each of these
     numeric priorities into a tuple of two numbers, the first of which is an
     increasing counter, the second of which is the client-generated priority