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

[a-h]

Description

• Small update to essay to add a tool.

Corresponding issue:

• No issue.

Testing

• Looked at the markdown files in the Github rendering display to check the markdown rendered as expected.

Checklist

• I have read the contribution guidelines
• I have targeted this PR against the correct branch (master for website changes, dev for
  source changes)
• This is either a bugfix, a documentation update, or a new feature that has been explicitly
  approved via an issue
• I ran the test suite locally (npm run test) and verified that it succeeded
  • I didn't run the test suite, because I didn't clone the repo, just used Github's markdown editor to propose the change.

[alexpetros]

thanks adrian!