docs: switch to plain bridgy logo

docs/conf.py

@@ -174,7 +174,7 @@ html_theme_options = {
 
 # The name of an image file (relative to this directory) to place at the top
 # of the sidebar.
-html_logo = '../static/bridgy_fed_logo.png'
+html_logo = '../static/bridgy_logo_with_alpha.png'
 
 # The name of an image file (within the static path) to use as favicon of the
 # docs.  This file should be a Windows icon file (.ico) being 16x16 or 32x32