Clarify how to think about rank aggregate

- Mention that `rank[1](...)` is the same as `min(...)`
- Make this (+ note about 1-based indexing) more visible

Author: shati-patel

docs/codeql/ql-language-reference/expressions.rst

@@ -308,7 +308,10 @@ The following aggregates are available in QL:
 
       rank[4](int i | i = [5 .. 15] | i)
 
-  Note that the rank indices start at ``1``, so ``rank[0](...)`` returns no results.
+  .. pull-quote:: Note
+
+     - Rank indices start at ``1``, so ``rank[0](...)`` returns no results.
+     - ``rank[1](...)`` is the same as ``min(...)``.
 
 .. index:: strictconcat, strictcount, strictsum