crystal: simplify installPhase as a follow-up to drop crystal_1_2 (#400564)

Changed files
+1 -2
pkgs
development
compilers
crystal
+1 -2
pkgs/development/compilers/crystal/default.nix
···
ln -s $bin/bin $out/bin
ln -s $bin/share/bash-completion $out/share/bash-completion
ln -s $bin/share/zsh $out/share/zsh
-
# fish completion was introduced in 1.6.0
-
test -f etc/completion.fish && ln -s $bin/share/fish $out/share/fish
+
ln -s $bin/share/fish $out/share/fish
ln -s $lib $out/lib
runHook postInstall