docs: It's difficult to estimate real-world usage from the benchmarks

Remove the prediction on real-world usage as it's not really practical
to make a prediction.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

docs/Debugging.md

@@ -188,9 +188,7 @@ The step rate benchmark is designed to find the maximum stepping rate
 that the hardware and software can reach. This benchmark stepping rate
 is not achievable in day-to-day use as Klipper needs to perform other
 tasks (eg, mcu/host communication, temperature reading, endstop
-checking) in any real-world usage. It is difficult to estimate actual
-real-world capacity, but as a general guide, one may approach 75% of
-these rates in practice.
+checking) in any real-world usage.
 
 ## Step rate benchmark test ##