Modify the status line to say "Field truncated" instead of "Warnings"

Currenly DML statements report status in this format:

Query OK, 1 row affected, 2 warnings (0.03 sec)

Rows matched: 1  Changed: 1  Warnings: 1

We'll change it to:

Query OK, 1 row affected, 2 warnings (0.03 sec)

Rows matched: 1  Changed: 1  Fields truncated: 1

to make it clearer that:

• the total number of warnings is reported in the first line
• the number of fields truncated in reported in the second line