Documentation: riscv: fix insufficient list item indent

When adding the ISA string ordering rules, I didn't sufficiently indent
one of the list items.
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/linux-doc/202301300743.bp7Dpazv-lkp@intel.com/
Fixes: f07b2b3f ("Documentation: riscv: add a section about ISA string ordering in /proc/cpuinfo")
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
Link: https://lore.kernel.org/r/20230129235701.2393241-1-conor@kernel.orgSigned-off-by: Palmer Dabbelt <palmer@rivosinc.com>

Documentation/riscv/uabi.rst

@@ -21,10 +21,10 @@ so for our purposes the following rules apply:
    single-letter extensions and before any higher-privileged extensions.
 
 #. For additional standard extensions, the first letter following the 'Z'
-  conventionally indicates the most closely related alphabetical
-  extension category. If multiple 'Z' extensions are named, they will be ordered
-  first by category, in canonical order, as listed above, then alphabetically
-  within a category.
+   conventionally indicates the most closely related alphabetical
+   extension category. If multiple 'Z' extensions are named, they will be
+   ordered first by category, in canonical order, as listed above, then
+   alphabetically within a category.
 
 #. Standard supervisor-level extensions (starting with 'S') will be listed
    after standard unprivileged extensions.  If multiple supervisor-level