docs: Correct '-runas' and '-fsdev/-virtfs proxy' indentation

Use the same style for deprecated / removed commands.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

docs/about/deprecated.rst

@@ -75,7 +75,7 @@ marked deprecated since 9.0, users have to ensure that all the topology members
 described with -smp are supported by the target machine.
 
 ``-runas`` (since 9.1)
-----------------------
+''''''''''''''''''''''
 
 Use ``-run-with user=..`` instead.
 

docs/about/removed-features.rst

@@ -518,7 +518,7 @@ and later do not support it because the virtio-scsi device was introduced for
 full SCSI support.  Use virtio-scsi instead when SCSI passthrough is required.
 
 ``-fsdev proxy`` and ``-virtfs proxy`` (since 9.2)
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+''''''''''''''''''''''''''''''''''''''''''''''''''
 
 The 9p ``proxy`` filesystem backend driver was originally developed to
 enhance security by dispatching low level filesystem operations from 9p