[LyX/master] Standard proof layout does not have an end label

[Jean-Marc Lasgouttes]

commit 5920ddb56709738e81a18b84ace788f85b3e6d44
Author: Jean-Marc Lasgouttes <lasgouttes at lyx.org>
Date:   Mon Jul 19 12:36:34 2021 +0200

    Standard proof layout does not have an end label
    
    Most proof environment have a qed box at the end, but not this one.
    This only changes screen rendering.
---
 lib/layouts/theorems-proof-std.inc |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/lib/layouts/theorems-proof-std.inc b/lib/layouts/theorems-proof-std.inc
index f42a61f..e6924f3 100644
--- a/lib/layouts/theorems-proof-std.inc
+++ b/lib/layouts/theorems-proof-std.inc
@@ -17,6 +17,7 @@ Style Proof
 		\providecommand{\proofname}{Proof}
 		\fi
 	EndPreamble
+	EndLabelType          No_Label
 # No LangPreamble or BabelPreamble, since babel knows \proofname already.
 	DocBookTag            para
 	DocBookAttr           role='proof'