Fix spelling errors in texi files: more informations --> more information allows to --> allows one to

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

doc/encoders.texi

@@ -1271,7 +1271,7 @@ Requires the presence of the libtheora headers and library during
 configuration. You need to explicitly configure the build with
 @code{--enable-libtheora}.
 
-For more informations about the libtheora project see
+For more information about the libtheora project see
 @url{http://www.theora.org/}.
 
 @subsection Options

doc/ffserver.texi

@@ -111,7 +111,7 @@ must be configured in the stream configuration. They are sent to
 the @command{ffmpeg} encoders.
 
 The @command{ffmpeg} @option{override_ffserver} commandline option
-allows to override the encoding parameters set by the server.
+allows one to override the encoding parameters set by the server.
 
 Multiple streams can be connected to the same feed.
 

doc/outdevs.texi

@@ -216,7 +216,7 @@ OpenGL output device.
 
 To enable this output device you need to configure FFmpeg with @code{--enable-opengl}.
 
-Device allows to render to OpenGL context.
+This output device allows one to render to OpenGL context.
 Context may be provided by application or default SDL window is created.
 
 When device renders to external context, application must implement handlers for following messages: