docs(essays): add templ to list of template languages that support fragments (#3382)

docs: add templ to template languages that support fragments

Author: a-h

www/content/essays/template-fragments.md

@@ -142,6 +142,7 @@ Here are some known implementations of the fragment concept:
 
 * Go
   * [Standard Library (use block actions)](https://pkg.go.dev/text/template) [[demo]](https://gist.github.com/benpate/f92b77ea9b3a8503541eb4b9eb515d8a)
+  * [templ](https://templ.guide) [[Fragment documentation]](https://templ.guide/syntax-and-usage/fragments) [[repo]](https://github.com/a-h/templ)
 * Java
   * [Thymeleaf](https://www.thymeleaf.org/doc/tutorials/3.0/usingthymeleaf.html#fragment-specification-syntax)
   * [Chill Templates (currently in early alpha)](https://github.com/bigskysoftware/chill/tree/master/chill-script)