Replace master with main in links and docs/conf.py (#100176)

Fixes #ISSUE_NUMBER

Pull Request resolved: https://github.com/pytorch/pytorch/pull/100176
Approved by: https://github.com/albanD, https://github.com/malfet

docs/cpp/source/conf.py

@@ -42,7 +42,7 @@ extensions = [
 ] if run_doxygen else [])
 
 intersphinx_mapping = {
-    'pytorch': ('https://pytorch.org/docs/master', None)
+    'pytorch': ('https://pytorch.org/docs/main', None)
 }
 
 # Setup absolute paths for communicating with breathe / exhale where
@@ -133,10 +133,10 @@ author = 'PyTorch Contributors'
 #
 # The short X.Y version.
 # TODO: change to [:2] at v1.0
-version = 'master'
+version = 'main'
 # The full version, including alpha/beta/rc tags.
 # TODO: verify this works as expected
-release = 'master'
+release = 'main'
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.