man: align strings in sd_notify() examples

I think this way it's easier to see that they are part of the same argument.

man/sd_notify.xml

@@ -533,8 +533,8 @@
 
       <programlisting>
 sd_notifyf(0, "READY=1\n"
-           "STATUS=Processing requests…\n"
-           "MAINPID=%lu",
+              "STATUS=Processing requests…\n"
+              "MAINPID=%lu",
            (unsigned long) getpid());</programlisting>
     </example>
 
@@ -545,7 +545,7 @@ sd_notifyf(0, "READY=1\n"
 
       <programlisting>
 sd_notifyf(0, "STATUS=Failed to start up: %s\n"
-           "ERRNO=%i",
+              "ERRNO=%i",
            strerror_r(errnum, (char[1024]){}, 1024),
            errnum);</programlisting>
     </example>