Update documentation for deprecation and removal of Close()

Doc/Manual/Extending.html

@@ -1500,12 +1500,11 @@ Create a File object wrapper around an existing <tt>FILE *</tt> object.
 </div>
 
 <p>
-<b><tt>int Close(String_or_FILE *f)</tt></b>
+There's no explicit function to close a file, just call <tt>Delete(f)</tt> -
+this decreases the reference count, and the file will be closed when the
+reference count reaches zero.
 </p>
 
-<div class="indent">
-<p>Closes a file.  Has no effect on strings.</p>
-
 <p>
 The use of the above I/O functions and strings play a critical role in SWIG.   It is
 common to see small code fragments of code generated using code like this:
@@ -2832,7 +2831,6 @@ int Python::top(Node *n) {
    Delete(f_header);
    Delete(f_wrappers);
    Delete(f_init);
-   Close(f_begin);
    Delete(f_begin);
 
    return SWIG_OK;

Source/DOH/README

@@ -65,7 +65,7 @@ Putc(ch,obj)                    Put a character
 Ungetc(ch,obj)                  Put character back on input stream
 Seek(obj,offset,whence)         Seek
 Tell(obj)                       Return file pointer
-Close(obj)                      Close
+Delete(obj)                     Decrease the reference count, close file if zero
 
 String Operations
 -----------------