Fix font for docs

Author: daniel-thom

docs/book.toml

@@ -13,7 +13,7 @@ create-missing = true
 default-theme = "light"
 preferred-dark-theme = "navy"
 git-repository-url = "https://github.com/NREL/torc"
-git-repository-icon = "fa-github"
+git-repository-icon = "github"
 edit-url-template = "https://github.com/NREL/torc/edit/main/docs/{path}"
 site-url = "/torc/"
 cname = ""