Improve match_body documentation

src/vmod_re.vcc

 #-
-# Copyright 2014-2018 UPLEX Nils Goroll Systemoptimierung
+# Copyright 2014-2023 UPLEX Nils Goroll Systemoptimierung
 # All rights reserved
 #
 # This document is licensed under the same conditions as the libvmod-re
@@ -20,9 +20,12 @@ SYNOPSIS
   import re;
 
   # object interface
-  new <obj> = re.regex(STRING, [, INT limit] [, INT limit_recursion])
+  new <obj> = re.regex(STRING, [, INT limit] [, INT limit_recursion]
+                       [, BOOL forbody])
   BOOL <obj>.match(STRING, [, INT limit] [, INT limit_recursion])
   STRING <obj>.backref(INT [, STRING fallback])
+  BOOL <obj>.match_body(req_body | bereq_body | resp_body,
+                        [, INT limit] [, INT limit_recursion])
 
   # function interface
   BOOL re.match_dyn(STRING, [, INT limit] [, INT limit_recursion])
@@ -73,18 +76,21 @@ The equivalent solution with the VMOD looks like this::
 		}
 	}
 
+For an example on body matching, see `xregex.match_body()`_.
+
 The object is created at VCL initialization with the regex containing
 the capture expression, only describing the substring to be
-matched. When a match with the ``match`` method succeeds, then a
-captured string can be obtained from the ``backref`` method.
+matched. When a match with the ``match`` or ``match_body`` method
+succeeds, then a captured string can be obtained from the ``backref``
+method.
 
 Calls to the ``backref`` method refer back to the most recent
-successful call to ``match`` for the same object in the same task
-scope; that is, in the same client or backend context. For example if
-``match`` is called for an object in one of the ``vcl_backend_*``
-subroutines and returns ``true``, then subsequent calls to ``backref``
-in the same backend scope extract substrings from the matched
-substring.
+successful call to ``match`` or ``match_body`` for the same object in
+the same task scope; that is, in the same client or backend
+context. For example if ``match`` is called for an object in one of
+the ``vcl_backend_*`` subroutines and returns ``true``, then
+subsequent calls to ``backref`` in the same backend scope extract
+substrings from the matched substring.
 
 The VMOD also supports dynamic regex matching with the ``match_dyn``
 and ``backref_dyn`` functions::