doc: escape minus sign in manpages
groff formats '-' as a hyphen, and '\-' is needed for a minus.
Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
diff --git a/extensions/libxt_esp.man b/extensions/libxt_esp.man
index 6a7cdea..699a41c 100644
--- a/extensions/libxt_esp.man
+++ b/extensions/libxt_esp.man
@@ -1,3 +1,3 @@
This module matches the SPIs in ESP header of IPsec packets.
.TP
-[\fB!\fP] \fB--espspi\fP \fIspi\fP[\fB:\fP\fIspi\fP]
+[\fB!\fP] \fB\-\-espspi\fP \fIspi\fP[\fB:\fP\fIspi\fP]