docs: device-mapper: fix typos in delay.rst and vdo-design.rst

Fixed the following typos in device-mapper documentation:
- explicitely -> explicitly
- approriate -> appropriate

Signed-off-by: Shubham Sharma <[e-mail]>
Signed-off-by: Mikulas Patocka <[e-mail]>

Documentation/admin-guide/device-mapper/delay.rst

···
    to write and flush operations on optionally different write_device with
    optionally different sector offset
 
-9: same as 6 arguments plus define flush_offset and flush_delay explicitely
+9: same as 6 arguments plus define flush_offset and flush_delay explicitly
    on/with optionally different flush_device/flush_offset.
 
 Offsets are specified in sectors.

Documentation/admin-guide/device-mapper/vdo-design.rst

···
 All storage within vdo is managed as 4KB blocks, but it can accept writes
 as small as 512 bytes. Processing a write that is smaller than 4K requires
 a read-modify-write operation that reads the relevant 4K block, copies the
-new data over the approriate sectors of the block, and then launches a
+new data over the appropriate sectors of the block, and then launches a
 write operation for the modified data block. The read and write stages of
 this operation are nearly identical to the normal read and write
 operations, and a single data_vio is used throughout this operation.