Escape single quotes in validation messages

[sdurrenmatt]

Validation messages that contain single quotes are not properly escaped, resulting in missing single quotes and uninterpreted format elements. For example, the French "pattern" validation message {0} ne correspond pas à l'expression régulière {1} with args $.foo and (foo)+ will result in $.foo ne correspond pas à lexpression régulière {1}.

See MessageFormat

Within a String, a pair of single quotes can be used to quote any arbitrary characters except single quotes. For example, pattern string "'{0}'" represents string "{0}", not a FormatElement. A single quote itself must be represented by doubled single quotes '' throughout a String. For example, pattern string "'{''}'" is interpreted as a sequence of '{ (start of quoting and a left curly brace), '' (a single quote), and }' (a right curly brace and end of quoting), not '{' and '}' (quoted left and right curly braces): representing string "{'}", not "{}".

Any unmatched quote is treated as closed at the end of the given pattern. For example, pattern string "'{0}" is treated as pattern "'{0}'".

[stevehu]

PR is merged.