[re.grammar] Avoid monospace font for ordinary text. (#4074)

Author: Eelis

source/regex.tex

@@ -3703,17 +3703,17 @@
 In addition the following expressions shall be equivalent:
 
 \begin{codeblock}
-\d and [[:digit:]]
+\d @\textnormal{and}@ [[:digit:]]
 
-\D and [^[:digit:]]
+\D @\textnormal{and}@ [^[:digit:]]
 
-\s and [[:space:]]
+\s @\textnormal{and}@ [[:space:]]
 
-\S and [^[:space:]]
+\S @\textnormal{and}@ [^[:space:]]
 
-\w and [_[:alnum:]]
+\w @\textnormal{and}@ [_[:alnum:]]
 
-\W and [^_[:alnum:]]
+\W @\textnormal{and}@ [^_[:alnum:]]
 \end{codeblock}
 
 \pnum