Re: Optimizer docs typos

In this same README doc, another suspicious typo to me, which happens in
section "Optimizer Functions", is in the prefix to query_planner(),
we should have three dashes, rather than two, since query_planner() is
called within grouping_planner().

diff --git a/src/backend/optimizer/README b/src/backend/optimizer/README
index 7dcab9a..bace081 100644
--- a/src/backend/optimizer/README
+++ b/src/backend/optimizer/README
@@ -315,7 +315,7 @@ set up for recursive handling of subqueries
   preprocess target list for non-SELECT queries
   handle UNION/INTERSECT/EXCEPT, GROUP BY, HAVING, aggregates,
        ORDER BY, DISTINCT, LIMIT
---query_planner()
+---query_planner()
    make list of base relations used in query
    split up the qual into restrictions (a=1) and joins (b=c)
    find qual clauses that enable merge and hash joins