fix typo

Author: coke

doc/Type/Code.rakudoc

@@ -200,7 +200,7 @@ say Food.^lookup('ingredients').line;  # OUTPUT: «1␤»
 
     method bytecode-size(--> Int:D)
 
-Note: this method has been available in Rakudo compiler on the MoarVM backend obnly, starting from 2022.06 release.
+Note: this method has been available in Rakudo compiler on the MoarVM backend only, starting from 2022.06 release.
 
 Returns the number of bytes that the code object occupies in memory.  Note
 that if the code object is in fact a C<multi>, then the bytecode size will