fix indentation for FAQ 10.6.1, update sitemap

We indent FAQ 10.6.1, added in a previous commit, in the
same way we indent 3rd level FAQ numbers.  Also adjusted
the vertical whitespace around the FAQ in `faq.md` to
be consistent with the other FAQ sections.

Updated sitemap.

Ran `make faq sitemap` to perform the above.

sitemap.xml

@@ -15454,11 +15454,11 @@
 </url>
 <url>
     <loc>https://www.ioccc.org/faq.html</loc>
-    <lastmod>2025-07-26T15:33:46+00:00</lastmod>
+    <lastmod>2025-08-01T17:13:12+00:00</lastmod>
 </url>
 <url>
     <loc>https://www.ioccc.org/faq.md</loc>
-    <lastmod>2025-07-26T09:01:09+00:00</lastmod>
+    <lastmod>2025-08-01T17:18:05+00:00</lastmod>
 </url>
 <url>
     <loc>https://www.ioccc.org/inc/index.html</loc>
@@ -15634,7 +15634,7 @@
 </url>
 <url>
     <loc>https://www.ioccc.org/status.html</loc>
-    <lastmod>2025-07-31T04:33:30+00:00</lastmod>
+    <lastmod>2025-08-01T17:13:33+00:00</lastmod>
 </url>
 <url>
     <loc>https://www.ioccc.org/status.json</loc>