patch 8.2.3482: reading beyond end of line ending in quote and backslash

Problem:    Reading beyond end of line ending in quote and backslash.
Solution:   Check for non-NUL after backslash. (closes #8964)
diff --git a/src/testdir/test_cindent.vim b/src/testdir/test_cindent.vim
index 5926408..3a536c4 100644
--- a/src/testdir/test_cindent.vim
+++ b/src/testdir/test_cindent.vim
@@ -5307,4 +5307,11 @@
   enew! | close
 endfunc
 
+func Test_backslash_at_end_of_line()
+  new
+  exe "norm v>O'\\\<C-m>-"
+  exe "norm \<C-q>="
+  bwipe!
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab