add pgformatter

doc/ale-sql.txt

@@ -2,6 +2,24 @@
 ALE SQL Integration                                           *ale-sql-options*
 
 
+===============================================================================
+pgformatter                                                 *ale-sql-pgformatter*
+
+g:ale_sql_pgformatter_executable             *g:ale_sql_pgformatter_executable*
+                                             *b:ale_sql_pgformatter_executable*
+  Type: |String|
+  Default: `'pg_format'`
+
+  This variable sets executable used for pgformatter.
+
+g:ale_sql_pgformatter_options                   *g:ale_sql_pgformatter_options*
+                                                *b:ale_sql_pgformatter_options*
+  Type: |String|
+  Default: `''`
+
+  This variable can be set to pass additional options to the pgformatter fixer.
+
+
 ===============================================================================
 sqlfmt                                                         *ale-sql-sqlfmt*