Clarify hammer-parse-step documentation

gdb-port/README.md

@@ -49,17 +49,19 @@ H_RULE(b, h_sequence(b_2, b_2, NULL));
 H_RULE(a_b, h_sequence(a, b, NULL));
 ```
 
-Stopping at `a_b` and invoking the command will stop at the applications of the following parsers:
+Stopping at `a_b` and invoking the command 4 times will stop at the applications of the following parsers:
 ```
 a, b, b_2, b_2
 ```
 
-Invoking `hammer-parse-step 2` would result in the following list:
+Stopping at `a_b` and invoking `hammer-parse-step 2` two times would result in the following list:
 
 ```
 b, b_2
 ```
 
+(Skipping over `a` and `b_2` once.)
+
 This is not equivalent to advancing the input stream by `[number]` bytes, rather, it is equivalent to running until the next `[number]` pushes on the parser stack. See also `hammer-parser-backtrace`.
 
 If the GDB parameter "hammer-extended-parse-step-info" is set to "on", it will also invoke hammer-parser-backtrace and hammer-parser-preview-input.