[iterator.concepts] Stop using LongTable for tables that aren't long.

Fixes an overfull hbox and reduces the risk of tables running off the
bottom of the page.

Author: zygoloid

source/iterators.tex

@@ -1899,18 +1899,12 @@
 the indicated semantics.
 \end{itemize}
 
-\begin{libreqtab4b}
+\begin{libreqtab4b}[floattable]
 {\oldconcept{Iterator} requirements}
 {iterator}
-\\ \topline
-\lhdr{Expression}   &   \chdr{Return type}  &   \chdr{Operational}  &   \rhdr{Assertion/note}       \\
-                    &                       &   \chdr{semantics}    &   \rhdr{pre-/post-condition}   \\ \capsep
-\endfirsthead
-\continuedcaption\\
-\hline
+\topline
 \lhdr{Expression}   &   \chdr{Return type}  &   \chdr{Operational}  &   \rhdr{Assertion/note}       \\
                     &                       &   \chdr{semantics}    &   \rhdr{pre-/post-condition}   \\ \capsep
-\endhead
 
 \tcode{*r}          &
   unspecified       &
@@ -2041,18 +2035,13 @@
 and the expressions in \tref{outputiterator}
 are valid and have the indicated semantics.
 
-\begin{libreqtab4b}
+\begin{libreqtab4b}[floattable]
 {\oldconcept{OutputIterator} requirements (in addition to \oldconcept{Iterator})}
 {outputiterator}
-\\ \topline
-\lhdr{Expression}   &   \chdr{Return type}  &   \chdr{Operational}  &   \rhdr{Assertion/note}       \\
-                    &                       &   \chdr{semantics}    &   \rhdr{pre-/post-condition}   \\ \capsep
-\endfirsthead
-\continuedcaption\\
-\hline
+\topline
 \lhdr{Expression}   &   \chdr{Return type}  &   \chdr{Operational}  &   \rhdr{Assertion/note}       \\
                     &                       &   \chdr{semantics}    &   \rhdr{pre-/post-condition}   \\ \capsep
-\endhead
+
 \tcode{*r = o}      &
  result is not used &
                     &
@@ -2143,18 +2132,13 @@
 allows the use of multi-pass one-directional algorithms with forward iterators.
 \end{note}
 
-\begin{libreqtab4b}
+\begin{libreqtab4b}[floattable]
 {\oldconcept{ForwardIterator} requirements (in addition to \oldconcept{InputIterator})}
 {forwarditerator}
-\\ \topline
-\lhdr{Expression}   &   \chdr{Return type}  &   \chdr{Operational}  &   \rhdr{Assertion/note}       \\
-                    &                       &   \chdr{semantics}    &   \rhdr{pre-/post-condition}   \\ \capsep
-\endfirsthead
-\continuedcaption\\
-\hline
+\topline
 \lhdr{Expression}   &   \chdr{Return type}  &   \chdr{Operational}  &   \rhdr{Assertion/note}       \\
                     &                       &   \chdr{semantics}    &   \rhdr{pre-/post-condition}   \\ \capsep
-\endhead
+
 \tcode{r++}         &
  convertible to \tcode{const X\&}   &
  \tcode{\{ X tmp = r;}\br
@@ -2184,18 +2168,13 @@
 in addition to meeting the \oldconcept{ForwardIterator} requirements,
 the following expressions are valid as shown in \tref{bidirectionaliterator}.
 
-\begin{libreqtab4b}
+\begin{libreqtab4b}[floattable]
 {\oldconcept{BidirectionalIterator} requirements (in addition to \oldconcept{ForwardIterator})}
 {bidirectionaliterator}
-\\ \topline
-\lhdr{Expression}   &   \chdr{Return type}  &   \chdr{Operational}  &   \rhdr{Assertion/note}       \\
-                    &                       &   \chdr{semantics}    &   \rhdr{pre-/post-condition}   \\ \capsep
-\endfirsthead
-\continuedcaption\\
-\hline
+\topline
 \lhdr{Expression}   &   \chdr{Return type}  &   \chdr{Operational}  &   \rhdr{Assertion/note}       \\
                     &                       &   \chdr{semantics}    &   \rhdr{pre-/post-condition}   \\ \capsep
-\endhead
+
 \tcode{\dcr r}      &
  \tcode{X\&}        &
                     &

source/tables.tex

@@ -301,14 +301,15 @@
  \end{LongTable}
 }
 
-\newenvironment{libreqtab4b}[2]
+\newenvironment{libreqtab4b}[3][LongTable]
 {
- \begin{LongTable}
- {#1}{#2}
+ \def\libreqtabenv{#1}
+ \begin{\libreqtabenv}
+ {#2}{#3}
  {x{.13\hsize}x{.15\hsize}x{.29\hsize}x{.27\hsize}}
 }
 {
- \end{LongTable}
+ \end{\libreqtabenv}
 }
 
 \newenvironment{libreqtab4c}[2]