[PATCH for-6.0 1/2] docs/system/gdb.rst: Add some more heading structure

[Peter Maydell <peter.maydell@linaro.org>]

We're about to add a new section to gdb.rst. In
preparation, add some more headings so it isn't just
one huge run-on section.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 docs/system/gdb.rst | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/docs/system/gdb.rst b/docs/system/gdb.rst
index 72b1e68f4ef..0bb1bedf1be 100644
--- a/docs/system/gdb.rst
+++ b/docs/system/gdb.rst
@@ -45,7 +45,11 @@ Here are some useful tips in order to use gdb on system code:
 3. Use ``set architecture i8086`` to dump 16 bit code. Then use
    ``x/10i $cs*16+$eip`` to dump the code at the PC position.
 
-Advanced debugging options:
+Advanced debugging options
+==========================
+
+Changing single-stepping behaviour
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 The default single stepping behavior is step with the IRQs and timer
 service routines off. It is set this way because when gdb executes a
@@ -88,6 +92,8 @@ three commands you can query and set the single step behavior:
       sending: "qemu.sstep=0x5"
       received: "OK"
 
+Examining physical memory
+^^^^^^^^^^^^^^^^^^^^^^^^^
 
 Another feature that QEMU gdbstub provides is to toggle the memory GDB
 works with, by default GDB will show the current process memory respecting
-- 
2.20.1