zsh: improve `shell{,Global}Aliases`

This commit changes the way aliases are rendered, adding the "no more
flags" flag `--`, which means that, for example, the alias `"-" = "cd
-";` will work as expected. (I was getting a syntax error before this
change.)

Additionally, now the alias key is shell escaped, which may help some
edge cases. I'm honestly not sure if this part is necessary since I
assume an alias can't contain spaces anyway, but it definitely
shouldn't break anything.

modules/programs/zsh.nix

@@ -15,7 +15,7 @@ let
   localVarsStr = config.lib.zsh.defineAll cfg.localVariables;
 
   aliasesStr = concatStringsSep "\n" (
-    mapAttrsToList (k: v: "alias ${k}=${lib.escapeShellArg v}") cfg.shellAliases
+    mapAttrsToList (k: v: "alias -- ${lib.escapeShellArg k}=${lib.escapeShellArg v}") cfg.shellAliases
   );
 
   dirHashesStr = concatStringsSep "\n" (
@@ -637,8 +637,8 @@ in
         # Aliases
         ${aliasesStr}
         ''
-      ] 
-      ++ (mapAttrsToList (k: v: "alias -g ${k}=${lib.escapeShellArg v}") cfg.shellGlobalAliases) 
+      ]
+      ++ (mapAttrsToList (k: v: "alias -g -- ${lib.escapeShellArg k}=${lib.escapeShellArg v}") cfg.shellGlobalAliases)
       ++ [ (''
         # Named Directory Hashes
         ${dirHashesStr}

tests/modules/programs/pls/zsh.nix

@@ -23,10 +23,10 @@ with lib;
       assertFileExists home-files/.zshrc
       assertFileContains \
         home-files/.zshrc \
-        "alias ls='@pls@/bin/pls'"
+        "alias -- 'ls'='@pls@/bin/pls'"
       assertFileContains \
         home-files/.zshrc \
-        "alias ll='@pls@/bin/pls -d perms -d user -d group -d size -d mtime -d git'"
+        "alias -- 'll'='@pls@/bin/pls -d perms -d user -d group -d size -d mtime -d git'"
     '';
   };
 }