Update a few links (#1261)

Co-authored-by: Ronny Pfannschmidt <[email protected]>

Author: Liam-DeVoe

changelog/1261.trivial.rst

@@ -0,0 +1 @@
+Update a few links in code comments.

src/xdist/newhooks.py

@@ -9,7 +9,7 @@
 You can use this hooks just as you would use normal pytest hooks, but some care
 must be taken in plugins in case ``xdist`` is not installed. Please see:
 
-    http://pytest.org/en/latest/writing_plugins.html#optionally-using-hooks-from-3rd-party-plugins
+    https://pytest.org/en/latest/how-to/writing_hook_functions.html#optionally-using-hooks-from-3rd-party-plugins
 """
 
 from __future__ import annotations

src/xdist/plugin.py

@@ -40,7 +40,7 @@ def cpu_count() -> int:
 
     except ImportError:
         if os.environ.get("TRAVIS") == "true":
-            # workaround https://bitbucket.org/pypy/pypy/issues/2375
+            # workaround https://github.com/pypy/pypy/issues/2375
             return 2
         try:
             from os import cpu_count  # type: ignore[assignment]