docs: Celsius typo (#468)

docs/Z_Calibration.md

@@ -72,7 +72,7 @@ But, there are some requirements to use it:
 Temperature or humindity changes are not a big deal since the switch is not
 affected much by them and all values are probed in a small time period and only
 the releations to each other are used. The nozzle height in step 2 can be
-determined some time later and even many celsius higher in the printer's
+determined some time later and even many Celsius higher in the printer's
 chamber, compared to the homing in step 1. That is why the nozzle is probed
 again and can vary a little to the first homing position.
 
@@ -286,4 +286,4 @@ at 250, you can preheat the nozzle to 180, and run this script before finishing
 temperature. This may have varying effects depending on temperatures used.
 
 Also consider picking up your probe prior to your nozzle wipe, to allow this script to probe the
-nozzle immediately after cleaning it.
+nozzle immediately after cleaning it.

klippy/extras/control_mpc.py

@@ -546,7 +546,7 @@ def process(eventtime):
                 ret = temp > target
                 if ret and not reported[0]:
                     gcmd.respond_info(
-                        f"Waiting for heater to drop below {target} degrees celcius"
+                        f"Waiting for heater to drop below {target} degrees Celsius"
                     )
                     reported[0] = True
                 return ret