[lex.pptoken] Simplify sentences with common cause

Author: AlisdairM

source/lex.tex

@@ -559,10 +559,9 @@
 literals), string literals (including user-defined string literals), preprocessing
 operators and punctuators, and single non-whitespace characters that do not lexically
 match the other preprocessing token categories.
-If a \unicode{0027}{apostrophe} or a \unicode{0022}{quotation mark} character
+If a \unicode{0027}{apostrophe}, a \unicode{0022}{quotation mark},
+or any character not in the basic character set
 matches the last category, the program is ill-formed.
-If any character not in the basic character set matches the last category,
-the program is ill-formed.
 Preprocessing tokens can be separated by
 \indextext{whitespace}%
 whitespace;