doc(snapshot_editor): updated docs

Added info about new `snapshot-editor` function.

Signed-off-by: Egor Lazarchuk <yegorlz@amazon.co.uk>

docs/snapshotting/snapshot-editor.md

@@ -10,11 +10,39 @@ Firecracker snapshot consists of 2 files:
   devices states etc.
 - `memory` file: file with guest memory.
 
-`snapshot-editor` (currently) allows to modify only `vmstate` files only
-on aarch64 platform.
-
 ## Usage
 
+### `edit-memory` command
+
+#### `rebase` subcommand
+
+This command is used to merge a `diff` snapshot memory file on
+top of a base memory file.
+
+**None**
+You can also use `rebase-snap` tool for this.
+
+Arguments:
+
+- `MEMORY_PATH` - path to the `memory` file
+- `DIFF_PATH` - path to the `diff` file
+
+Usage:
+
+```bash
+snapshot-editor edit-memory rebase \
+     --memory-path <MEMORY_PATH> \
+     --diff-path <DIFF_PATH>
+```
+
+Example:
+
+```bash
+snapshot-editor edit-memory rebase \
+     --memory-path ./memory_file \
+     --diff-path ./diff_file
+```
+
 ### `edit-vmstate` command
 
 #### `remove-regs` subcommand (aarch64 only)

docs/snapshotting/snapshot-support.md

@@ -244,12 +244,23 @@ created by a subsequent `/snapshot/create` API call. The order in which the
 snapshots were created matters and they should be merged in the same order
 in which they were created. To merge a `diff` snapshot memory file on
 top of a base, users should copy its content over the base. This can be done
-using the `rebase-snap` tool provided with the firecracker release:
+using the `rebase-snap` or `snapshot-editor` tools provided with the
+firecracker release:
+
+`rebase-snap` example:
 
 ```bash
 rebase-snap --base-file path/to/base --diff-file path/to/layer
 ```
 
+`snapshot-editor` example:
+
+```bash
+snapshot-editor edit-memory rebase \
+     --memory-path path/to/base \
+     --diff-path path/to/layer
+```
+
 After executing the command above, the base would be a resumable snapshot memory
 file describing the state of the memory at the moment of creation of the layer.
 More layers which were created later can be merged on top of this base.