[docs] Clarify that developer dependencies require the JDK not just t…

…he JRE (#12968)

hail/python/hail/docs/getting_started_developing.rst

@@ -6,11 +6,13 @@ Hail is an open-source project. We welcome contributions to the repository.
 Requirements
 ~~~~~~~~~~~~
 
-- `Java 8 or 11 JDK <https://adoptopenjdk.net/index.html>`_
+- `Java 8 or 11 JDK <https://adoptopenjdk.net/index.html>`_.
   Note: it *must* be Java **8** or Java **11**. Hail does not support versions 9-10 or 12+ due to
   our dependency on Spark.
 
-- The Python and non-pip installation requirements in `Getting Started <getting_started.html>`_
+- The Python and non-pip installation requirements in `Getting Started <getting_started.html>`_.
+  Note: These instructions install the JRE but that is not necessary as the JDK should already
+  be installed which includes the JRE.
 
 - If you are setting `HAIL_COMPILE_NATIVES=1`, then you need the LZ4 library
   header files. On Debian and Ubuntu machines run: `apt-get install liblz4-dev`.