ZF-6764: Minor misconception in Zend_Validate messages processing

Description

According to existing documentation getMessages() method returns a list of validation failure messages as => pairs.

It's declared, that getErrors() value can be also get calling array_keys() on the return value from getMessages().

But different validators in the validator chain may have the same message keys, so some messages may be lost.

It also produces problems in Zend_Filter_Input, which uses validators conception for messages processing. All rule validation errors messages are stored within one array.

Comments

Actually every validator uses another key.

Keys are using a syntax like "validatorKey"... f.e. "dateFalseFormat" or "stringFalseFormat".