Documentation fix

Author: isoos

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## 2.3.0-null-safety.0
 
 - Migrate to null safety. (Thanks to [j4qfrost](https://github.com/j4qfrost), [#153](https://github.com/stablekernel/postgresql-dart/pull/153)).
+- Documentation fix (by [saward](https://github.com/saward)).
 
 ## 2.2.0
 

lib/src/connection.dart

@@ -204,7 +204,7 @@ class PostgreSQLConnection extends Object
   /// Queries within a transaction may be executed asynchronously or be awaited on. The order is still guaranteed. Example:
   ///
   ///         connection.transaction((ctx) {
-  ///           var rows = await ctx.query("SELECT id FROM t);
+  ///           var rows = await ctx.query("SELECT id FROM t");
   ///           if (!rows.contains([2])) {
   ///             ctx.query("INSERT INTO t (id) VALUES (2)");
   ///           }