Fish shell doesn't require arguments to `eval` to be double quoted
like in a bash shell. At the moment doing so gives us the following
error:
~/.config/fish/config.fish (line 12): $(...) is not supported. In fish, please use '(/nix/store/8asq…)'.
eval "$(/nix/store/8asqgnhs89wzyjvs8p1n5hvxn7lkn9wa-opam-2.1.3/bin/opam env --shell=fish)"
^
from sourcing file ~/.config/fish/config.fish
called during startup
source: Error while reading file “/home/user/.config/fish/config.fish”
This commit fixes the above error.
