[intro.defs] Remove unused definitions

The terms "arbitrary-positional stream", "repositional stream",
and "iostream class templates" are removed.

Fixes ISO/CS 011 and ISO/CS 16 (C++23 DIS).

Author: jensmaurer

source/intro.tex

@@ -127,16 +127,6 @@
 although they may involve accesses of scalar subobjects.
 \end{defnote}
 
-\definition{arbitrary-positional stream}{defns.arbitrary.stream}
-\defncontext{library}
-\indexdefn{stream!arbitrary-positional}%
-stream that can seek to any integral position within
-the length of the stream
-
-\begin{defnote}
-Every arbitrary-positional stream is also a repositional stream\iref{defns.repositional.stream}.
-\end{defnote}
-
 \indexdefn{argument}%
 \indexdefn{argument!function call expression}
 \definition{argument}{defns.argument}
@@ -350,20 +340,6 @@
 \definition{implementation limits}{defns.impl.limits}
 restrictions imposed upon programs by the implementation
 
-\definition{iostream class templates}{defns.iostream.templates}
-\defncontext{library}
-templates that are declared in header \libheader{iosfwd} and
-take two template arguments
-
-\begin{defnote}
-The arguments are named \tcode{charT} and \tcode{traits}.
-The argument \tcode{charT} is a character container class, and
-the argument \tcode{traits} is a class
-which defines additional characteristics and functions
-of the character type represented by \tcode{charT}
-necessary to implement the iostream class templates.
-\end{defnote}
-
 \indexdefn{behavior!locale-specific}%
 \definition{locale-specific behavior}{defns.locale.specific}
 behavior that depends on local conventions of nationality, culture, and
@@ -514,11 +490,6 @@
 definitions of all translation units\iref{basic.link}.
 \end{defnote}
 
-\definition{repositional stream}{defns.repositional.stream}
-\defncontext{library}
-\indexdefn{stream!repositional}%
-stream that can seek to a position that was previously encountered
-
 \definition{required behavior}{defns.required.behavior}
 \defncontext{library}
 \indexdefn{behavior!required}%

source/xrefdelta.tex

@@ -22,6 +22,11 @@
 % P2874R2 Mandating Annex D
 \removedxref{depr.res.on.required}
 
+% DIS comment **-011
+\removedxref{defns.arbitrary.stream}
+\removedxref{defns.repositional.stream}
+\removedxref{defns.iostream.templates}
+
 %%% Renamed sections.
 %%% Examples:
 %