ValidationMessages: improve message a bit.

No functional changes.

Author: php-coder

src/main/resources/ru/mystamps/i18n/ValidationMessages.properties

@@ -24,7 +24,7 @@ ru.mystamps.web.validation.jsr303.MaxFileSize.message = File size must be not gr
 
 value.too-short = Value is less than allowable minimum of {min} characters
 value.too-long = Value is greater than allowable maximum of {max} characters
-value.invalid-length = Value length must be equals to {max} characters
+value.invalid-length = Value length must be equal to {max} characters
 value.invalid-en-chars = Value must consist only latin letters, hyphen or spaces
 value.invalid-ru-chars = Value must consist only Russian letters, hyphen or spaces
 value.hyphen = Value must not start or end with hyphen