patch 9.1.0574: ex: wrong handling of commands after bar

Problem:  ex: wrong handling of commands after bar
Solution: for :append, :insert and :change use the text after the bar
          as input for those commands. This is what POSIX requests.
          (Mohamed Akram)

See the POSIX Spec:
https://pubs.opengroup.org/onlinepubs/9699919799/utilities/ex.html#tag_20_40_13_03
Section 12.c

closes: #15229

Signed-off-by: Mohamed Akram <mohd.akram@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/ex_docmd.c b/src/ex_docmd.c
index 7ab1c69..614ba20 100644
--- a/src/ex_docmd.c
+++ b/src/ex_docmd.c
@@ -5401,7 +5401,11 @@
 		    && in_vim9script()
 		    && !(eap->argt & EX_NOTRLCOM)
 		    && p > eap->cmd && VIM_ISWHITE(p[-1]))
-		|| *p == '|' || *p == '\n')
+		|| (*p == '|'
+		    && eap->cmdidx != CMD_append
+		    && eap->cmdidx != CMD_change
+		    && eap->cmdidx != CMD_insert)
+		|| *p == '\n')
 	{
 	    /*
 	     * We remove the '\' before the '|', unless EX_CTRLV is used