document values row (docs also test)

Signed-off-by: Sean Corfield <sean@corfield.org>

doc/clause-reference.md

@@ -1305,6 +1305,21 @@ In addition, all of the rows are padded to the same length by adding `nil`
 values if needed (since `:values` does not know how or if column
 names are being used in this case).
 
+### values row (MySQL)
+
+MySQL supports `VALUES` as a table expression in multiple
+contexts, and it uses "row constructors" to represent the
+rows of values.
+
+HoneySQL supports this by using the keyword `:row` (or
+symbol `'row`) as the first element of a sequence of values.
+
+
+```clojure
+user=> (sql/format {:values [:row [1 2] [3 4]]})
+["VALUES ROW(?, ?), ROW(?, ?)" 1 2 3 4]
+```
+
 ### values examples
 
 ```clojure

src/honey/sql.cljc

@@ -2370,6 +2370,10 @@
   (format {:select [:a [:b :c] [[:d :e]] [[:f :g] :h]]})
   (format {:select [[[:d :e]] :a [:b :c]]})
   (format {:values [:row [1 2] [3 4]]})
+  (format {:with [[[:stuff {:columns [:id :name]}]
+                   {:values [:row [1 "Sean"] [2 "Jay"]]}]]
+           :select [:id :name]
+           :from [:stuff]})
   (format-on-expr :where [:= :id 1])
   (format-dsl {:select [:*] :from [:table] :where [:= :id 1]})
   (format {:select [:t.*] :from [[:table :t]] :where [:= :id 1]} {})