Move `sphinx.ext.intersphinx` into a package

Co-authored-by: Adam Turner <9087854+aa-turner@users.noreply.github.com>

.ruff.toml

@@ -395,7 +395,7 @@ select = [
 "sphinx/environment/adapters/toctree.py" = ["B026"]
 
 # whitelist ``print`` for stdout messages
-"sphinx/ext/intersphinx.py" = ["T201"]
+"sphinx/ext/intersphinx/__init__.py" = ["T201"]
 
 # whitelist ``print`` for stdout messages
 "sphinx/testing/fixtures.py" = ["T201"]
@@ -503,7 +503,7 @@ exclude = [
     "sphinx/ext/mathjax.py",
     "sphinx/ext/doctest.py",
     "sphinx/ext/autosectionlabel.py",
-    "sphinx/ext/intersphinx.py",
+    "sphinx/ext/intersphinx/__init__.py",
     "sphinx/ext/duration.py",
     "sphinx/ext/imgconverter.py",
     "sphinx/ext/imgmath.py",

sphinx/ext/intersphinx/__init__.py

@@ -850,10 +850,3 @@ def inspect_main(argv: list[str], /) -> int:
         return 1
     else:
         return 0
-
-
-if __name__ == '__main__':
-    import logging as _logging
-    _logging.basicConfig()
-
-    raise SystemExit(inspect_main(sys.argv[1:]))

sphinx/ext/intersphinx/__main__.py

@@ -0,0 +1,10 @@
+"""Command line interface for the intersphinx extension."""
+
+import logging as _logging
+import sys
+
+from sphinx.ext.intersphinx import inspect_main
+
+_logging.basicConfig()
+
+raise SystemExit(inspect_main(sys.argv[1:]))