Update bugs/README for 1998/schnitzi

I removed from bugs.md the suggestion that it does not work for macOS as
I fixed that. I also slightly reworded the entry in bugs.md (about
warnings to ignore).

Add to README.md summary of problem.

1998/schnitzi/README.md

@@ -29,7 +29,8 @@
 	./sort < data
 
 [Cody Boone Ferguson](/winners.html#Cody_Boone_Ferguson) fixed a segfault in
-this entry. Thank you Cody for your assistance!
+this entry. The problem was invalid data types. Thank you Cody for your
+assistance!
 
 ## Judges' comments
 

bugs.md

@@ -328,9 +328,6 @@ If you get the compiler warning:
 
 please do NOT change it! Doing so will break the generated output.
 
-It does not currently work under macOS. This will be investigated in the near
-future.
-
 Another warning to ignore is:
 
 
@@ -338,7 +335,7 @@ Another warning to ignore is:
 	   55 | main(int v,char **c){ O=r_; _d=c;
 	      |                               ^
 
-Please do not change this.
+Please do not change this either.
 
 # 2000