Make important fix in FAQ about git fetch

After my final commit and merge in mkiocccentry pre-release a pull did
not get the tag. I had to do:

    git fetch --all --tags

instead. So to make sure everyone has the correct tag I have added this
to the FAQ (replacing the 'git fetch' by itself).

Regenerated faq.html.

faq.md

@@ -278,7 +278,7 @@ If you already have an mkiocccentry tool directory:
 
 ``` <!---sh-->
     cd mkiocccentry
-    git fetch
+    git fetch --all --tags
     git rebase
 ```