doc: fix after snaptools merge

doc/functions/snap/example-firefox.nix

@@ -0,0 +1,28 @@
+let
+  inherit (import <nixpkgs> { }) snapTools firefox;
+in snapTools.makeSnap {
+  meta = {
+    name = "nix-example-firefox";
+    summary = firefox.meta.description;
+    architectures = [ "amd64" ];
+    apps.nix-example-firefox = {
+      command = "${firefox}/bin/firefox";
+      plugs = [
+        "pulseaudio"
+        "camera"
+        "browser-support"
+        "avahi-observe"
+        "cups-control"
+        "desktop"
+        "desktop-legacy"
+        "gsettings"
+        "home"
+        "network"
+        "mount-observe"
+        "removable-media"
+        "x11"
+      ];
+    };
+    confinement = "strict";
+  };
+}

doc/functions/snap/example-hello.nix

@@ -0,0 +1,12 @@
+let
+  inherit (import <nixpkgs> { }) snapTools hello;
+in snapTools.makeSnap {
+  meta = {
+    name = "hello";
+    summary = hello.meta.description;
+    description = hello.meta.longDescription;
+    architectures = [ "amd64" ];
+    confinement = "strict";
+    apps.hello.command = "${hello}/bin/hello";
+  };
+}

doc/functions/snaptools.xml

@@ -38,7 +38,7 @@
    <para>
     The following expression packages GNU Hello as a Snapcraft snap.
    </para>
-<programlisting><xi:include href="../../pkgs/build-support/snap/example-hello.nix" parse="text" /></programlisting>
+<programlisting><xi:include href="./snap/example-hello.nix" parse="text" /></programlisting>
    <para>
     <command>nix-build</command> this expression and install it with
     <command>snap install ./result --dangerous</command>.
@@ -57,7 +57,7 @@
     example uses Firefox as an example, because it is one of the most
     complicated programs we could package.
    </para>
-<programlisting><xi:include href="../../pkgs/build-support/snap/example-firefox.nix" parse="text" /></programlisting>
+<programlisting><xi:include href="./snap/example-firefox.nix" parse="text" /></programlisting>
    <para>
     <command>nix-build</command> this expression and install it with
     <command>snap install ./result --dangerous</command>.