Remove manual quoting of option arguments

[frederik-elwert]

Subprocess handles the quoting of arguments, so there is no need to manually quote them in case they contain a space. In fact, the quotes will be escaped by subprocess, so the argument value will contain the literal quotes.

I noticed this when passing font names to the latex template:

latex:
    o: '%.tex'
    number-sections:
    variable:
        - documentclass:scrartcl
        - mainfont:Linux Libertine
        - sansfont:Linux Biolinum