zsh: correctly handle autoloading functions starting with '-'

tests/modules/programs/zsh/default.nix

@@ -22,7 +22,7 @@
   zsh-legacy-warning = ./legacy-warning.nix;
   zsh-oh-my-zsh-custom = ./oh-my-zsh-custom.nix;
   zsh-plugins-completions-renamed = ./plugins-completions-renamed.nix;
-  zsh-siteFunctions-mkcd = ./siteFunctions-mkcd.nix;
+  zsh-siteFunctions = ./siteFunctions.nix;
   zsh-plugins = ./plugins.nix;
   zsh-prezto = ./prezto.nix;
   zsh-session-variables = ./session-variables.nix;

tests/modules/programs/zsh/siteFunctions-mkcd.nix

@@ -1,17 +0,0 @@
-let
-  body = ''
-    mkdir --parents "$1" && cd "$1"
-  '';
-in
-{
-  programs.zsh = {
-    enable = true;
-    siteFunctions.mkcd = body;
-  };
-
-  nmt.script = ''
-    assertFileExists home-path/share/zsh/site-functions/mkcd
-    assertFileContent home-path/share/zsh/site-functions/mkcd ${builtins.toFile "mkcd" body}
-    assertFileContains home-files/.zshrc "autoload -Uz mkcd"
-  '';
-}

tests/modules/programs/zsh/siteFunctions.nix

@@ -0,0 +1,23 @@
+let
+  mkcd-body = ''
+    mkdir --parents "$1" && cd "$1"
+  '';
+  hidden-body = ''
+    echo "doing some hidden magic"
+  '';
+in
+{
+  programs.zsh = {
+    enable = true;
+    siteFunctions.mkcd = mkcd-body;
+    siteFunctions."-hidden-function" = hidden-body;
+  };
+
+  nmt.script = ''
+    assertFileExists home-path/share/zsh/site-functions/mkcd
+    assertFileExists home-path/share/zsh/site-functions/-hidden-function
+    assertFileContent home-path/share/zsh/site-functions/mkcd ${builtins.toFile "mkcd" mkcd-body}
+    assertFileContent home-path/share/zsh/site-functions/-hidden-function ${builtins.toFile "-hidden-function" hidden-body}
+    assertFileContains home-files/.zshrc "autoload -Uz -- -hidden-function mkcd"
+  '';
+}