Update nop.md

see #696

docs/commands/nop.md

@@ -3,11 +3,16 @@
 The `nop` command allows you to easily skip instructions.
 
 ```
-gef➤ nop [-b NUM_BYTES] [-h] [LOCATION]
+gef ➤  help nop
+Patch the instruction(s) pointed by parameters with NOP. Note: this command is architecture
+aware.
+Syntax: nop [LOCATION] [--nb NUM_BYTES]
+  LOCATION      address/symbol to patch
+    --nb NUM_BYTES      Instead of writing one instruction, patch the specified number of bytes
 ```
 
 `LOCATION` indicates the address of the instruction to bypass. If not
 specified, it will use the current value of the program counter.
 
-If `-b <bytes>` is entered, gef will explicitly patch the specified number of
+If `--nb <bytes>` is entered, gef will explicitly patch the specified number of
 bytes.  Otherwise it will patch the _whole_ instruction at the target location.