explain why web docs use carlito

explain why the web docs are using the fallback, mostly to demystify why we're showing an example that is displaying an error like message.

Author: story645

galleries/examples/misc/logos2.py

@@ -24,6 +24,7 @@ def get_font_properties():
     if 'calibri' in matplotlib.font_manager.findfont('Calibri:bold').lower():
         return matplotlib.font_manager.FontProperties(family='Calibri',
                                                       weight='bold')
+    # Our website documentation uses Carlito because Calibri is proprietary.
     if 'carlito' in matplotlib.font_manager.findfont('Carlito:bold').lower():
         print('Original font not found. Falling back to Carlito. '
               'The logo text will not be in the correct font.')