Allow for fuzzy tag searches; making it easier to analyze how you spent a given time period

Use Case: I do a monthly review each month where I look back at the previous month, what worked, what didn't etc. I also like to see how much time I spent on various endeavors. I use time warrior to track nearly all the time of what I'm doing during the day.

So I'm looking back at last month with : timew month :lastmonth

I'd like to see how much time I spent playing the guitar but the trouble is, sometimes I've entered the time as 'guitar practice' and sometimes simply 'guitar'...

But if I search with: timew month :lastmonth guitar ... it doesn't seem to find the gutiar practice times.... Now one could argue, 'these are two totally different tags'... but I think there should be perhaps an option specified during search that allows any matches.

Another nicety would be case insenstive searching.

Another nicey would be some kind of tab completion integration into fish shell or bash or zsh (but preferrably fish :P)

Thanks again for the great software!

No files or tests are named. Reproduce the monthly search with `timew month :lastmonth guitar`, then trace how tag matching handles exact and case-sensitive terms. Confirm with maintainers whether fuzzy matching, case-insensitive search, and shell completion are all in scope; done should define the accepted matching behavior.

Written by the indexing model from the issue text.