Update WDL class context

[vortexing]

URL of existing content (a rendered, sciwiki.fredhutch.org link)

https://sciwiki.fredhutch.org/datascience/hutch_courses/#wdl-101

Specific information requests or concerns, or specific region on page of content to refresh.

We should update this text to be more accurate for our current offerings.

@ GitHub username of the listed primary reviewer of the page if known

@caalo or @sitapriyamoorthi