2020-10-31: Error vs Exception

[baileythegreen]

The terms error and exception are both used in the glossary—which is fine—but they seem to be conflated and used interchangeably, probably due to a mix of authors.

Because the two terms are not equal, I propose either:

• only including one, so terms like error_handling and exception_handler are consistent, or
• clearly delineating the differences between the terms.

[fmichonneau]

@gvwilson what are your thoughts on this?