bash prompt: use bash builtins to check stash state

diff --git a/RelNotes b/RelNotes
index bcb4fb98ff925389797125283e40c6e397efc1fd..fce99fb79d16cbeb717ddbe36c7be231a00e4eba 120000 (symlink)
--- a/RelNotes
+++ b/RelNotes
@@ -1 +1 @@
-Documentation/RelNotes/1.7.11.txt
\ No newline at end of file
+Documentation/RelNotes/1.8.4.txt
\ No newline at end of file