[LyX/2.3.x] Add hint to warning.

[Juergen Spitzmueller]

commit 76e71c5fddd420d29d48c5a53075ec66fd96a140
Author: Juergen Spitzmueller <spitz at lyx.org>
Date:   Tue May 21 13:26:57 2019 +0200

    Add hint to warning.
    
    (cherry picked from commit 957e8669c74b45542606d8271ef49d592a3704f1)
---
 src/insets/InsetCommandParams.cpp |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/src/insets/InsetCommandParams.cpp b/src/insets/InsetCommandParams.cpp
index 64725ca..09a76a1 100644
--- a/src/insets/InsetCommandParams.cpp
+++ b/src/insets/InsetCommandParams.cpp
@@ -521,7 +521,8 @@ docstring InsetCommandParams::prepareCommand(OutputParams const & runparams,
 			// FIXME: should be passed to the error dialog
 			frontend::Alert::warning(_("Uncodable characters in inset"),
 				bformat(_("The following characters in one of the insets are\n"
-					  "not representable in the current encoding and have been omitted:\n%1$s."),
+					  "not representable in the current encoding and have been omitted: %1$s.\n"
+					  "Unchecking 'Literal' in the respective inset dialog might help."),
 				uncodable));
 		}
 	}