present: remove extraneous line

There was an extra line in the documentation for the
present package that appears to be a copy paste from the
previous paragraph. This removes that line.

Fixes #21891

Change-Id: Ic50840b2210e3d93ac452a659e29b6feaa33c7b7
Reviewed-on: https://go-review.googlesource.com/63811
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/present/doc.go b/present/doc.go
index bd395eb..1eae9c8 100644
--- a/present/doc.go
+++ b/present/doc.go
@@ -85,10 +85,6 @@
 a single marker character becomes a space and a doubled single
 marker quotes the marker character.
 
-at the beginning of a line or
-else be preceded by a space or punctuation; similarly a closing
-marker must be at the end of the lineo
-
 	_italic_
 	*bold*
 	`program`