update for R 4.5.x

git-svn-id: https://svn.r-project.org/R/trunk@89027 00db46b3-68df-0310-9c12-caf00c1e9a41

Author: ripley

doc/manual/R-admin.texi

@@ -1098,9 +1098,9 @@ if you want to specify a non-default standard use something like
 Compiling @R{} requires C99 or later: C11 and C17 are minor updates, but
 the substantial update `C23' (finally published in October 2024) is also
 supported for recent versions of GCC@footnote{At least 13--15: 15
-defaults to C23},  @command{clang}@footnote{including @I{LLVM} clang 18--20
-and Apple clang 15--17.} and Intel @command{icx}.  @R{} 4.5.0 defaults
-to C23 if supported by the chosen compiler.
+defaults to C23}, @command{clang}@footnote{including @I{LLVM} clang
+18--20 and Apple clang 15--17.} and Intel @command{icx}.  @R{} 4.5.0 and
+later default to C23 if supported by the chosen compiler.
 
 As from @R{} 4.3.0 there is support for packages to indicate their
 preferred C version.  Macros @code{CC17}, @code{C17FLAGS}, @code{CC23}