[span.cons] Fix typos in P1394R4.

Do not attempt to initialize size_ with an iterator.
Properly use sized_sentinel_for<End, It>.

Author: jensmaurer

source/containers.tex

@@ -10709,7 +10709,7 @@
 \pnum
 \effects
 Initializes \tcode{data_} with \tcode{to_address(first)} and
-\tcode{size_} with \tcode{first + count}.
+\tcode{size_} with \tcode{count}.
 
 \pnum
 \throws
@@ -10734,7 +10734,7 @@
 of the iterator reference type to \tcode{element_type}.
 \end{note}
 \item \tcode{It} satisfies \libconcept{contiguous_iterator}.
-\item \tcode{End} satisfies \tcode{\libconcept{sized_sentinel_for}<It>}.
+\item \tcode{End} satisfies \tcode{\libconcept{sized_sentinel_for}<End, It>}.
 \item \tcode{is_convertible_v<End, size_t>} is \tcode{false}.
 \end{itemize}
 
@@ -10745,7 +10745,7 @@
 then \tcode{last - first} is equal to \tcode{extent}.
 \item \range{first}{last} is a valid range.
 \item \tcode{It} models \libconcept{contiguous_iterator}.
-\item \tcode{End} models \tcode{\libconcept{sized_sentinel_for}<It>}.
+\item \tcode{End} models \tcode{\libconcept{sized_sentinel_for}<End, It>}.
 \end{itemize}
 
 \pnum