[genius] Fix string, thanks to Anders Jonsson

[George Lebl <jirka src gnome org>]

commit 7897e73c8d07bce14b814215499c9f4f2e3861cd
Author: Jiri (George) Lebl <jiri lebl gmail com>
Date:   Thu Sep 22 09:02:50 2016 -0500

    Fix string, thanks to Anders Jonsson

 help/C/genius.xml |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/help/C/genius.xml b/help/C/genius.xml
index ded95b8..4a1dddf 100644
--- a/help/C/genius.xml
+++ b/help/C/genius.xml
@@ -8961,7 +8961,7 @@ optionally the limits as <userinput>x1,x2,y1,y2</userinput>.
           <para>
            Returns a row vector of a point on the line plot corresponding to
            the current mouse location.  If the line plot is not visible,
-           then prints and error and returns <constant>null</constant>.
+           then prints an error and returns <constant>null</constant>.
            In this case you should run
            <link linkend="gel-function-LinePlot"><function>LinePlot</function></link> or
            <link linkend="gel-function-LinePlotClear"><function>LinePlotClear</function></link>