Merge 2023-06 CWG Motion 5

P2558R2 Add @, $, and ` to the basic character set

Author: tkoeppe

source/lex.tex

@@ -262,7 +262,7 @@
 
 \pnum
 The \defnadj{basic}{character set} is a subset of the translation character set,
-consisting of 96 characters as specified in \tref{lex.charset.basic}.
+consisting of 99 characters as specified in \tref{lex.charset.basic}.
 \begin{note}
 Unicode short names are given only as a means to identifying the character;
 the numerical value has no other meaning in this context.
@@ -279,6 +279,7 @@
 \ucode{0021} & \uname{exclamation mark} & \tcode{!} \\
 \ucode{0022} & \uname{quotation mark} & \tcode{"} \\
 \ucode{0023} & \uname{number sign} & \tcode{\#} \\
+\ucode{0024} & \uname{dollar sign} & \tcode{\$} \\
 \ucode{0025} & \uname{percent sign} & \tcode{\%} \\
 \ucode{0026} & \uname{ampersand}  & \tcode{\&} \\
 \ucode{0027} & \uname{apostrophe} & \tcode{'} \\
@@ -297,13 +298,15 @@
 \ucode{003d} & \uname{equals sign} & \tcode{=} \\
 \ucode{003e} & \uname{greater-than sign} & \tcode{>} \\
 \ucode{003f} & \uname{question mark} & \tcode{?} \\
+\ucode{0040} & \uname{commercial at} & \tcode{@} \\
 \ucode{0041} .. \ucode{005a} & \uname{latin capital letter a .. z} & \tcode{A B C D E F G H I J K L M} \\
  & & \tcode{N O P Q R S T U V W X Y Z} \\
 \ucode{005b} & \uname{left square bracket} & \tcode{[} \\
 \ucode{005c} & \uname{reverse solidus} & \tcode{\textbackslash} \\
 \ucode{005d} & \uname{right square bracket} & \tcode{]} \\
 \ucode{005e} & \uname{circumflex accent} & \tcode{\caret} \\
 \ucode{005f} & \uname{low line} & \tcode{_} \\
+\ucode{0060} & \uname{grave accent} & \tcode{\`} \\
 \ucode{0061} .. \ucode{007a} & \uname{latin small letter a .. z} & \tcode{a b c d e f g h i j k l m} \\
  & & \tcode{n o p q r s t u v w x y z} \\
 \ucode{007b} & \uname{left curly bracket} & \tcode{\{} \\