Add a sniff for <title> which contains HTML escape codes

[fulldecent]

A new test for built HTML files:

The title element has text. And that text must not contain:

&

and other obvious HTML encoding mistakes.

I guess the matcher could be:

m/\&[a-z]+;/i

[fulldecent]

Here is one such found error (that was not on a <title>):

➜  public-websites egrep -i '\&[a-z]+;' *-sites/*.*/build/**/*.html
atc-sites/rnmobility.com/build/hawaiice.html:    Hawai'i: RN license renewal & continuing ed