add examples of :alias with :group-by

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

doc/clause-reference.md

@@ -1091,6 +1091,11 @@ user=> (sql/format '{select (*) from (table)
 ["SELECT * FROM table GROUP BY status, YEAR(created_date)"]
 ```
 
+You can `GROUP BY` expressions, column names (`:col1`), or table and column (`:table.col1`),
+or aliases (`:some.alias`). Since there is ambiguity between the formatting
+of those, you can use the special syntax `[:alias :some.thing]` to tell
+HoneySQL to treat `:some.thing` as an alias instead of a table/column name.
+
 ## having
 
 The `:having` clause works identically to `:where` above

doc/special-syntax.md

@@ -29,6 +29,14 @@ and strings.
              :from :b
              :order-by [[[:alias :'some-alias]]]})
 ;;=> ["SELECT column_name AS \"some-alias\" FROM b ORDER BY \"some-alias\" ASC"]
+(sql/format {:select [[:column-name "some-alias"]]
+             :from :b
+             :group-by [[:alias "some-alias"]]})
+;;=> ["SELECT column_name AS \"some-alias\" FROM b GROUP BY \"some-alias\""]
+(sql/format {:select [[:column-name "some-alias"]]
+             :from :b
+             :group-by [[:alias :'some-alias]]})
+;;=> ["SELECT column_name AS \"some-alias\" FROM b GROUP BY \"some-alias\""]
 ```
 
 ## array