fixed tag link to be more robust

[mbc3]

this changes the tag link to work on sites installed on sub-directory, such as "/linux". Removing the leading slash makes this work, though I must admit I don't know why, as I'm relatively new to Hugo. I tested this out on my own site and it works.

[jmooring]

https://gohugo.io/methods/page/getterms/ is not fragile.