Remove instances of "Don't worry" from the user's guide

To use a consistent voice in the IGB User's Guide the IGB team has decided to follow the guidelines outlined in the Microsoft Manual of Style.

On page 5 of the manual it says that we shouldn't apply omniscience and assume that we know how someone is feeling.

This means removing phrases such as "Don't worry" from the user's guide.

If there's a potential concern we should anticipate it and address it.

I only found one instance of this in the user's guide so far:

https://wiki.transvar.org/display/igbman/RNA-Seq+Coverage+graphs+-+Visualizing+data+from+maize+reproductive+transcriptomes
The page above contains sentences that reads, "DON'T WORRY if you accidentally add a different data set. You can remove it by unchecking the box or clicking the red x."

We may want to change this to, "If you accidentally add a different data set you can remove it by unchecking the box or clicking the red x."

If more instances are found they will be added to comments below.