* doc/lispref/strings.texi (Case Conversion): Avoid problems with
ligatures in printed versions of the manual. (Bug#29818)
result may differ compared to treating a one-character string. For
example:
+@ifnottex
@example
@group
(upcase "fi") ; note: single character, ligature "fi"
@result{} 64257 ; i.e. ?fi
@end group
@end example
+@end ifnottex
+@iftex
+@example
+@group
+(upcase "fi") ; note: single character, ligature "fi"
+ @result{} "FI"
+@end group
+@group
+(upcase ?fi)
+ @result{} 64257 ; i.e. ?fi
+@end group
+@end example
+@end iftex
To avoid this, a character must first be converted into a string,
using @code{string} function, before being passed to one of the casing