Escaping aria-label in footer links

[Baltazardoung]

Fix #2735

[squidfunk]

Thanks for the PR. Please make sure to also make your changes in the src folder:
https://github.com/squidfunk/mkdocs-material/blob/master/src/partials/footer.html

See https://squidfunk.github.io/mkdocs-material/customization/#theme-development

Never make any changes in the material directory, as the contents of this directory are automatically generated from the src directory and will be overridden when the theme is built.

[Baltazardoung]

Thanks for the PR. Please make sure to also make your changes in the src folder:
https://github.com/squidfunk/mkdocs-material/blob/master/src/partials/footer.html

Fixed !