Mention GraalPy in other implementaion section

Author: aisk

index.rst

@@ -217,14 +217,16 @@ CPython, they always have more things they would like to do than they have
 developers to work on them.  Some major examples that may be of interest are:
 
 * PyPy_: A Python interpreter focused on high speed (JIT-compiled) operation
-  on major platforms
+  on major platforms.
 * Jython_: A Python interpreter focused on good integration with the Java
-  Virtual Machine (JVM) environment
+  Virtual Machine (JVM) environment.
+* GraalPy: Another Python interpreter which has first-class support for
+  embedding in Java, built on GraalVM.
 * IronPython_: A Python interpreter focused on good integration with the
-  Common Language Runtime (CLR) provided by .NET and Mono
+  Common Language Runtime (CLR) provided by .NET and Mono.
 * Stackless_: A Python interpreter focused on providing lightweight
   microthreads while remaining largely compatible with CPython specific
-  extension modules
+  extension modules.
 * MicroPython_: A tiny Python interpreter with small subset of the Python
   standard library that is optimised to run on microcontrollers and in
   constrained environments.