QVT — Escape characters in string literals

The escape characters used in string literals need to be adequately defined
or referenced.
Note: This issue is related to issue: 9427

In relation with resolution 9427, replace the sentence:

"All the usual escape characters using backslash can be used including the '\n' return-line character."

By
"""
All the usual escape characters using backslash can be used including the '\n' return-line character. The list of available escape characters are those defined for the Java language.

EscapeSequence:
\ b /* \u0008: backspace BS */
\ t /* \u0009: horizontal tab HT */
\ n /* \u000a: linefeed LF */
\ f /* \u000c: form feed FF */
\ r /* \u000d: carriage return CR */
\ " /* \u0022: double quote" */
\ ' /* \u0027: single quote ' */
\ \ /* \u005c: backslash \ */
OctalEscape /* \u0000 to \u00ff: from octal value

OctalEscape:
\ OctalDigit
\ OctalDigit OctalDigit
\ ZeroToThree OctalDigit OctalDigit
OctalDigit: one of
0 1 2 3 4 5 6 7
ZeroToThree: one of
0 1 2 3
"""