[Docs] Drop duplicate [source] links

Author: russellb

docs/source/conf.py

@@ -37,7 +37,6 @@
 # ones.
 extensions = [
     "sphinx.ext.napoleon",
-    "sphinx.ext.viewcode",
     "sphinx.ext.linkcode",
     "sphinx.ext.intersphinx",
     "sphinx_copybutton",