You are 100% correct. I'm not about to change it at this time though, just too many files around with the wrong spelling. Can we agree that it's a MMA quirk
If it really bothers you, add the following line to your initialization file:
Patch Rename DistortonGuitar=DistortionGuitar
You could also do the same thing with "Patch Set 30=DistortonGuitar" but that will generate a warning.
If anyone has a suggestion for a "better" solution ... do let me know!!! BTW, this bug has been in MMA for about 10 or 15 years
I, for one, never type in the names ... I just copy/paste from the HTML docs. Yup, I'm a crappy typist.