Reprioritize WITH wrt UNION and UNION ALL

WITH needs to come before clauses that are part of a UNION
or UNION ALL.[1][2][3][4]

[1] "A CTE must be followed by a single SELECT, INSERT, UPDATE, or DELETE
statement that references some or all the CTE columns."
https://docs.microsoft.com/en-us/sql/t-sql/queries/with-common-table-expression-transact-sql

[2] "the WITH clause itself is attached to a primary statement that can
also be a SELECT, INSERT, UPDATE, or DELETE"
https://www.postgresql.org/docs/9.6/static/queries-with.html

[3] https://mariadb.com/kb/en/mariadb/with/

[4] "All common table expressions (ordinary and recursive) are created
by prepending a WITH clause in front of a SELECT, INSERT, DELETE, or
UPDATE statement."
https://sqlite.org/lang_with.html

Added a test case demonstrating the expected behavior for each of
UNION and UNION ALL.

src/honeysql/format.cljc

@@ -183,10 +183,10 @@
 
 (def default-clause-priorities
   "Determines the order that clauses will be placed within generated SQL"
-  {:union 20
-   :union-all 25
-   :with 30
-   :with-recursive 40
+  {:with 20
+   :with-recursive 30
+   :union 40
+   :union-all 45
    :select 50
    :insert-into 60
    :update 70

test/honeysql/format_test.cljc

@@ -121,3 +121,18 @@
            (format {:select [:foo]
                     :from [:bar]
                     :where [:= [:mod :col1 4] [:+ :col2 4]]})))))
+
+(deftest union-with-cte
+  (is (= (format {:union [{:select [:foo] :from [:bar1]}
+                          {:select [:foo] :from [:bar2]}]
+                  :with [[[:bar {:columns [:spam :eggs]}]
+                          {:values [[1 2] [3 4] [5 6]]}]]})
+         ["WITH bar (spam, eggs) AS (VALUES (?, ?), (?, ?), (?, ?)) SELECT foo FROM bar1 UNION SELECT foo FROM bar2" 1 2 3 4 5 6])))
+
+
+(deftest union-all-with-cte
+  (is (= (format {:union-all [{:select [:foo] :from [:bar1]}
+                              {:select [:foo] :from [:bar2]}]
+                  :with [[[:bar {:columns [:spam :eggs]}]
+                          {:values [[1 2] [3 4] [5 6]]}]]})
+         ["WITH bar (spam, eggs) AS (VALUES (?, ?), (?, ?), (?, ?)) SELECT foo FROM bar1 UNION ALL SELECT foo FROM bar2" 1 2 3 4 5 6])))