Update docs.

Author: LindleyF

Doc/Manual/Java.html

@@ -6439,6 +6439,11 @@ <H3><a name="Java_special_variables">27.9.7 Java special variables</a></H3>
 unless the jniclassname attribute is specified in the <a href="Java.html#Java_module_directive">%module directive</a>.
 </p>
 
+<p>
+<b><tt>$imfuncname</tt></b><br>
+This special variable expands to the name of the function on the $imclassname that will be used in $jnicall.
+</p>
+
 <p>
 <b><tt>$javainterfacename</tt></b><br>
 This special variable is only expanded when the <tt>interface</tt> feature is applied to a class.