Allow capitalization for social icon tooltips

[gregorni]

Currently, the social icons are assigned a name in config.toml, which must be lowercase to be recognized properly (i.e. github instead of Github or GitHub). These names are then also used for the tooltips when hovering one of the icons. However, lowercase looks weird in a tooltip.

It would be nice if these names could be Uppercase as well, or any arbitrary case for that matter, to allow for uppercase tooltips. The name could then be converted to lowercase before assigned an icon.