Use descending sorting for _valid versions_

It makes more sense to show `latest  stable  <newest>` than `<oldest>` first.
#11069 (comment)

Author: humitos

readthedocs/projects/tests/test_version_handling.py

@@ -39,10 +39,10 @@ def test_sort_versions_python_packaging(self):
         expected = [
             # `latest` and `stable` are at the beginning
             "latest",
-            "v1.0",
+            "2.5.3",
             "1.1",
             "1.1.0",
-            "2.5.3",
+            "v1.0",
             # Invalid versions are at the end sorted alphabetically.
             "another-invalid",
             "invalid",
@@ -72,10 +72,10 @@ def test_sort_versions_python_packaging_latest_stable_not_at_beginning(self):
         ]
 
         expected = [
-            "v1.0",
+            "2.5.3",
             "1.1",
             "1.1.0",
-            "2.5.3",
+            "v1.0",
             # Invalid versions are at the end sorted alphabetically.
             "another-invalid",
             "invalid",
@@ -116,10 +116,10 @@ def test_sort_versions_calver(self):
             # `latest` and `stable` are at the beginning
             "latest",
             "stable",
-            "2021.01.22",
-            "2022.01.22",
-            "2022.05.02",
             "2023.04.22",
+            "2022.05.02",
+            "2022.01.22",
+            "2021.01.22",
             # invalid ones (alphabetically)
             "1.1",
             "1.1.0",
@@ -171,9 +171,9 @@ def test_sort_versions_custom_pattern(self):
             # `latest` and `stable` are at the beginning
             "latest",
             "stable",
-            "v1.0",
-            "v1.1",
             "v2.3",
+            "v1.1",
+            "v1.0",
             # invalid ones (alphabetically)
             "1.1",
             "2.5.3",

readthedocs/projects/version_handling.py

@@ -204,7 +204,7 @@ def sort_versions_python_packaging(version_list, latest_stable_at_beginning):
 
     all_versions = (
         initial_versions
-        + sorted(valid_versions, key=operator.itemgetter(1))
+        + sorted(valid_versions, key=operator.itemgetter(1), reverse=True)
         + invalid_versions
     )
 
@@ -265,7 +265,7 @@ def sort_versions_custom_pattern(version_list, raw_pattern, latest_stable_at_beg
 
     all_versions = (
         initial_versions
-        + sorted(valid_versions, key=operator.itemgetter(1))
+        + sorted(valid_versions, key=operator.itemgetter(1), reverse=True)
         + invalid_versions
     )