[algorithms] Change stable label "mismatch" to "alg.mismatch" (#6653)

Author: ojrosten

source/algorithms.tex

@@ -977,7 +977,7 @@
         count_if(R&& r, Pred pred, Proj proj = {});
   }
 
-  // \ref{mismatch}, mismatch
+  // \ref{alg.mismatch}, mismatch
   template<class InputIterator1, class InputIterator2>
     constexpr pair<InputIterator1, InputIterator2>
       mismatch(InputIterator1 first1, InputIterator1 last1,
@@ -4044,7 +4044,7 @@
 of the corresponding predicate and any projection.
 \end{itemdescr}
 
-\rSec2[mismatch]{Mismatch}
+\rSec2[alg.mismatch]{Mismatch}
 
 \indexlibraryglobal{mismatch}%
 \begin{itemdecl}

source/xrefdelta.tex

@@ -33,6 +33,9 @@
 % https://github.com/cplusplus/draft/pull/6255
 \movedxref{container.gen.reqmts}{container.requirements.general}
 
+% https://github.com/cplusplus/draft/pull/6653
+\movedxref{mismatch}{alg.mismatch}
+
 %%% Deprecated features.
 %%% Example:
 %