nixos/doc: fix mention of reading test logs

nixos/doc/manual/development/running-nixos-tests.section.md

@@ -24,8 +24,8 @@ After building/downloading all required dependencies, this will perform
 a build that starts a QEMU/KVM virtual machine containing a NixOS
 system. The virtual machine mounts the Nix store of the host; this makes
 VM creation very fast, as no disk image needs to be created. Afterwards,
-you can view a pretty-printed log of the test:
+you can view a log of the test:
 
 ```ShellSession
-$ firefox result/log.html
+$ nix-store --read-log result
 ```

nixos/doc/manual/from_md/development/running-nixos-tests.section.xml

@@ -26,9 +26,9 @@ machine: QEMU running (pid 8841)
     perform a build that starts a QEMU/KVM virtual machine containing a
     NixOS system. The virtual machine mounts the Nix store of the host;
     this makes VM creation very fast, as no disk image needs to be
-    created. Afterwards, you can view a pretty-printed log of the test:
+    created. Afterwards, you can view a log of the test:
   </para>
   <programlisting>
-$ firefox result/log.html
+$ nix-store --read-log result
 </programlisting>
 </section>