[allocator.requirements] Fix footnote within Table 31 and table placement

Author: tkoeppe

source/lib-intro.tex

@@ -1824,8 +1824,6 @@
 \tcode{args}    &   a function parameter pack with the pattern \tcode{Args\&\&} \\
 \end{libreqtab2}
 
-\newpage
-
 \begin{libreqtab4d}
 {Allocator requirements}
 {tab:utilities.allocator.requirements}
@@ -1906,7 +1904,11 @@
 
 \tcode{a.allocate(n)}   &   \tcode{X::pointer}  &
 Memory is allocated for \tcode{n} objects of type \tcode{T} but objects
-are not constructed. \tcode{allocate} may throw an appropriate exception.\footnotemark
+are not constructed. \tcode{allocate} may throw an appropriate exception.%
+\footnote{It is intended that \tcode{a.allocate} be an efficient means
+of allocating a single object of type \tcode{T}, even when \tcode{sizeof(T)}
+is small. That is, there is no need for a container to maintain its own
+free list.}
 \begin{note}
 If \tcode{n == 0}, the return value is unspecified.
 \end{note}              &  \\ \rowsep
@@ -2016,11 +2018,6 @@
 
 \end{libreqtab4d}
 
-\footnotetext{It is intended that \tcode{a.allocate} be an efficient means
-of allocating a single object of type \tcode{T}, even when \tcode{sizeof(T)}
-is small. That is, there is no need for a container to maintain its own
-free list.}
-
 \pnum
 Note A: The member class template \tcode{rebind} in the table above is
 effectively a typedef template. \begin{note} In general, if