Template keywords should parse commas out

[Hachmann]

When I use the new 'Save template...' functionality in master, and I enter keywords like this:

flyer, A6, fold,

the keywords get split by spaces, but the commas will be interpreted as being part of the keyword.

Please:

1. Add an example tooltip that explains how it's supposed to work
2. Allow for commas - it feels unnatural and unintuitive to enter keywords just separated by spaces.

(0.92+devel (14d07e6, 2018-08-17), LM 18.3)

(Thanks for having added that functionality! I totally overlooked it until now - but always wanted it :) It will be so much easier to explain to people how to create their own templates now :D)