[lex.key] Don't use a colon to introduce a floating table.

This table floated off to a different page, so the colon pointed
nowhere.

Author: zygoloid

source/lex.tex

@@ -747,7 +747,11 @@
 \indextext{keyword|(}%
 The identifiers shown in \tref{lex.key} are reserved for use
 as keywords (that is, they are unconditionally treated as keywords in
-phase 7) except in an \grammarterm{attribute-token}\iref{dcl.attr.grammar}:
+phase 7) except in an \grammarterm{attribute-token}\iref{dcl.attr.grammar}.
+\begin{note}
+The \keyword{register} keyword is unused but
+is reserved for future use.
+\end{note}
 
 \begin{multicolfloattable}{Keywords}{lex.key}
 {lllll}
@@ -838,11 +842,6 @@
 \keyword{while} \\
 \end{multicolfloattable}
 
-\begin{note}
-The \keyword{register} keyword is unused but
-is reserved for future use.
-\end{note}
-
 \pnum
 Furthermore, the alternative representations shown in
 \tref{lex.key.digraph} for certain operators and