Remove "in a nutshell" from title of CrystFEL highlight page

During the review, I missed that the words "in a nutshell" would be used in the title of the highlight on the index page (https://www.hifis.net/spotlights.html). CrystFEL is the only one with these words, and it looks out of place and suggests that the name of the software has something to do with almonds, cashews, pistachios or even squirrels 🙂

This merge request simply removes "in a nutshell" from a couple of places. Based on the MR from when the spotlight was added, I believe this is all that's needed to fix the text.