Add missing NEWPAGE commands to makedoc markup in reent/

makedoc requires a NEWPAGE command to preceed the second and subsequent FUNCTION
commands in a file in order to produce the correct texinfo output.

Add missing NEWPAGE commands needed in reent/execr.c. and reent/signalr.c, which
contain makedoc markup for multiple functions.

Signed-off-by: Jon TURNEY <jon.turney@dronecode.org.uk>

newlib/libc/reent/execr.c

@@ -69,6 +69,7 @@ _DEFUN (_execve_r, (ptr, name, argv, env),
 
 
 /*
+NEWPAGE
 FUNCTION
 	<<_fork_r>>---Reentrant version of fork
 	
@@ -107,6 +108,7 @@ _DEFUN (_fork_r, (ptr),
 #endif
 
 /*
+NEWPAGE
 FUNCTION
 	<<_wait_r>>---Reentrant version of wait
 	

newlib/libc/reent/signalr.c

@@ -64,6 +64,7 @@ _DEFUN (_kill_r, (ptr, pid, sig),
 }
 
 /*
+NEWPAGE
 FUNCTION
 	<<_getpid_r>>---Reentrant version of getpid