ENH: adding irsa favicon

Author: bsipocz

_static/irsa-favicon.ico

@@ -73,7 +73,7 @@
 html_theme = 'sphinx_book_theme'
 html_title = 'IRSA Demo Notebooks'
 html_logo = '_static/irsa_logo.png'
-#html_favicon = '_static/favicon.ico'
+html_favicon = '_static/irsa-favicon.ico'
 html_theme_options = {
     "github_url": "https://github.com/Caltech-IPAC/irsa-tutorials",
     "repository_url": "https://github.com/Caltech-IPAC/irsa-tutorials",