[lex] Rename U+0007 BELL to ALERT

The former is ambiguous with U+1F514 BELL.
The ALERT alias is defined in UCD NameAliases.txt.

Author: jensmaurer

source/lex.tex

@@ -322,11 +322,16 @@
 The \defnadj{basic literal}{character set} consists of
 all characters of the basic character set,
 plus the control characters specified in \tref{lex.charset.literal}.
+\begin{note}
+The alias \uname{bell} for \ucode{0007} shown in ISO 10646
+is ambiguous with \unicode{1f514}{bell}.
+\end{note}
+
 \begin{floattable}{Additional control characters in the basic literal character set}{lex.charset.literal}{ll}
 \topline
 \ohdrx{2}{character} \\ \capsep
 \ucode{0000} & \uname{null} \\
-\ucode{0007} & \uname{bell} \\
+\ucode{0007} & \uname{alert} \\
 \ucode{0008} & \uname{backspace} \\
 \ucode{000d} & \uname{carriage return} \\
 \end{floattable}
@@ -1503,7 +1508,7 @@
 \ucode{0008} & \uname{backspace}            & \tcode{\textbackslash b} \\
 \ucode{000d} & \uname{carriage return}      & \tcode{\textbackslash r} \\
 \ucode{000c} & \uname{form feed}            & \tcode{\textbackslash f} \\
-\ucode{0007} & \uname{bell}                 & \tcode{\textbackslash a} \\
+\ucode{0007} & \uname{alert}                & \tcode{\textbackslash a} \\
 \ucode{005c} & \uname{reverse solidus}      & \tcode{\textbackslash\textbackslash} \\
 \ucode{003f} & \uname{question mark}        & \tcode{\textbackslash ?} \\
 \ucode{0027} & \uname{apostrohpe}           & \tcode{\textbackslash '} \\