patch 8.2.4925: trailing backslash may cause reading past end of line

Problem:    Trailing backslash may cause reading past end of line.
Solution:   Check for NUL after backslash.
diff --git a/src/testdir/test_textobjects.vim b/src/testdir/test_textobjects.vim
index debbfb3..34894d0 100644
--- a/src/testdir/test_textobjects.vim
+++ b/src/testdir/test_textobjects.vim
@@ -185,10 +185,18 @@
     call assert_equal("<div><div\nattr=\"attr\"\n></div></div>", @", e)
 
     set quoteescape&
+
+    " this was going beyond the end of the line
+    %del
+    sil! norm i"\
+    sil! norm i"\
+    sil! norm i"\
+    call assert_equal('"\', getline(1))
+
+    bwipe!
   endfor
 
   set enc=utf-8
-  bwipe!
 endfunc
 
 func Test_empty_html_tag()
diff --git a/src/textobject.c b/src/textobject.c
index e4a7db3..edaa64c 100644
--- a/src/textobject.c
+++ b/src/textobject.c
@@ -1664,7 +1664,11 @@
 	if (c == NUL)
 	    return -1;
 	else if (escape != NULL && vim_strchr(escape, c))
+	{
 	    ++col;
+	    if (line[col] == NUL)
+		return -1;
+	}
 	else if (c == quotechar)
 	    break;
 	if (has_mbyte)
diff --git a/src/version.c b/src/version.c
index d790a75..8f33f05 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4925,
+/**/
     4924,
 /**/
     4923,