Add documentation for new long string format

doc/sphinx/reference/vcl.rst

@@ -84,7 +84,7 @@ Strings
 
 Basic strings are enclosed in double quotes ``"``\ *...*\ ``"``, and
 may not contain newlines. Long strings are enclosed in
-``{"``\ *...*\ ``"}``. They may contain any character including single
+``{"``\ *...*\ ``"}`` or ``"""``\ *...*\ ``"""``. They may contain any character including single
 double quotes ``"``, newline and other control characters except for the
 *NUL* (0x00) character.
 
@@ -511,7 +511,7 @@ ban(STRING)
 
       Either a literal string or a regular expression. Note that
       *<arg>* does not use any of the string delimiters like ``"`` or
-      ``{"``\ *...*\ ``"}`` used elsewhere in varnish. To match
+      ``{"``\ *...*\ ``"}`` or ``"""``\ *...*\ ``"""`` used elsewhere in varnish. To match
       against strings containing whitespace, regular expressions
       containing ``\s`` can be used.
 

doc/sphinx/users-guide/vcl-syntax.rst

@@ -23,7 +23,7 @@ to do the "count-the-backslashes" polka::
 
   regsub("barf", "(b)(a)(r)(f)", "\4\3\2p") -> "frap"
 
-Long strings are enclosed in {" ... "}. They may contain any character
+Long strings are enclosed in {" ... "} or """ ... """. They may contain any character
 including ", newline and other control characters except for the NUL
 (0x00) character. If you really want NUL characters in a string there
 is a VMOD that makes it possible to create such strings.