[LyX/master] Improve tool tip for the new DocBook MathML-prefix option.

[Thibaut Cuvelier]

commit 6102327d3b69c1caf1e931f98e22396cca425720
Author: Thibaut Cuvelier <tcuvelier at lyx.org>
Date:   Tue Mar 23 21:28:44 2021 +0100

    Improve tool tip for the new DocBook MathML-prefix option.
---
 src/frontends/qt/ui/OutputUi.ui |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/src/frontends/qt/ui/OutputUi.ui b/src/frontends/qt/ui/OutputUi.ui
index ba04619..7aa75a7 100644
--- a/src/frontends/qt/ui/OutputUi.ui
+++ b/src/frontends/qt/ui/OutputUi.ui
@@ -100,7 +100,7 @@
          </font>
         </property>
         <property name="toolTip">
-         <string>Namespace prefix to use for MathML formulae.</string>
+         <string>Namespace prefix to use for MathML formulae. For instance, with the <code>m</code> prefix, the MathML tags will be output like <code>m:math</code>.</string>
         </property>
         <item>
          <property name="text">