[gnumeric] ssconvert: document --verbose

[Morten Welinder <mortenw src gnome org>]

commit 4ba4f241c0392af4c89e96b6a90a3d530d899c48
Author: Morten Welinder <terra gnome org>
Date:   Sun Jan 20 13:02:08 2019 -0500

    ssconvert: document --verbose

 doc/ssconvert.1 | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/doc/ssconvert.1 b/doc/ssconvert.1
index 572abf07c..b325e51f4 100644
--- a/doc/ssconvert.1
+++ b/doc/ssconvert.1
@@ -31,6 +31,9 @@ starting with two dashes (`--').
 .B \-\-recalc
 Recalculate all cells before writing the result.
 .TP
+.B \-v, \-\-verbose
+Be slightly more verbose about what is going on.
+.TP
 .B \-\-list\-exporters
 List the available exporters (file formats that can be written).
 .TP