docs: fix step in transition plan

One of the required steps for the objectFormat extension is to implement
the loose object index.  However, without support for
compatObjectFormat, we don't even know if the loose object index is
needed, so it makes sense to move that step to the compatObjectFormat
section.  Do so.

Signed-off-by: brian m. carlson <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: bk2204

Documentation/technical/hash-function-transition.txt

@@ -650,14 +650,14 @@ Some initial steps can be implemented independently of one another:
 
 The first user-visible change is the introduction of the objectFormat
 extension (without compatObjectFormat). This requires:
-- implementing the loose-object-idx
 - teaching fsck about this mode of operation
 - using the hash function API (vtable) when computing object names
 - signing objects and verifying signatures
 - rejecting attempts to fetch from or push to an incompatible
   repository
 
 Next comes introduction of compatObjectFormat:
+- implementing the loose-object-idx
 - translating object names between object formats
 - translating object content between object formats
 - generating and verifying signatures in the compat format