patch 8.2.4719: ">" marker sometimes not displayed in the jumplist

Problem:    ">" marker sometimes not displayed in the jumplist.
Solution:   If the buffer no longer exists show "-invalid-". (Christian
            Brabandt, closes #10131, closes #10100)
diff --git a/src/mark.c b/src/mark.c
index fbb4b9a..e7addbe 100644
--- a/src/mark.c
+++ b/src/mark.c
@@ -871,6 +871,10 @@
 	{
 	    name = fm_getname(&curwin->w_jumplist[i].fmark, 16);
 
+	    // Make sure to output the current indicator, even when on an wiped
+	    // out buffer.  ":filter" may still skip it.
+	    if (name == NULL && i == curwin->w_jumplistidx)
+		name = vim_strsave((char_u *)"-invalid-");
 	    // apply :filter /pat/ or file name not available
 	    if (name == NULL || message_filtered(name))
 	    {