patch 8.2.2246: cursor keys not recognized at the hit-Enter prompt

Problem:    Cursor keys not recognized at the hit-Enter prompt after executing
            an external command.
Solution:   Change the codes for the extra cursor keys. (closes #7562)
            Tune the delays to avoid test flakyness.
diff --git a/runtime/doc/term.txt b/runtime/doc/term.txt
index 87e5624..0093a96 100644
--- a/runtime/doc/term.txt
+++ b/runtime/doc/term.txt
@@ -217,6 +217,10 @@
 Another speciality about these codes is that they are not overwritten by
 another code.  That is to avoid that the codes obtained from xterm directly
 |t_RV| overwrite them.
+
+Another special value is a termcap entry ending in "@;*X".  This is for cursor
+keys, which either use "CSI X" or "CSI 1 ; modifier X".  Thus the "@"
+stands for either "1" if a modifier follows, or nothing.
 							*xterm-scroll-region*
 The default termcap entry for xterm on Sun and other platforms does not
 contain the entry for scroll regions.  Add ":cs=\E[%i%d;%dr:" to the xterm