Create Preformatted TagHelper

[hishamco]

Nine days ago I created a repo to put all my useful tag helpers in one place, similar to what you are doing in this repo, but I came across an issue with the <pre> tag to write some explanatory text about the usage of each tag. I already logged the issue here and surprisingly when I look to your commit here I found the ugly encoded html markup. IMHO it would be nice to create a tag helper that do the encoding in our behalf. I'm not sure why we didn't have it at all?!!

I already created in my local repo, if this fine for you I can make a PR for that