chap-architecture: Remove mention of CToPtr and CFromPtr.

These instructions are now deprecated and treated as optional the
rationale section on DDC/PCC offsetting.

chap-architecture.tex

@@ -1622,14 +1622,6 @@ \section{Capability-Aware Instructions}
 \insnref{CSetFlags}, \insnref{CSetHigh}, and
 \insnref{CSetOffset}.
 
-\item[Derive integer pointers from capabilities, or capabilities from integer
-pointers]
-The \insnref{CToPtr} and \insnref{CFromPtr} instructions efficiently
-convert between integer pointers and capabilities, performing suitable bounds
-checks against contextual capabilities.
-These support efficient hybrid code, in which use of integer pointers and
-capabilities are intermixed.
-
 \item[Capability pointer comparison]
 These instructions provide pointer comparison:
 \insnref{CSetEqualExact} and