lavfi: add missing periods in filter descriptions.

libavfilter/af_channelsplit.c

@@ -137,7 +137,7 @@ static const AVFilterPad avfilter_af_channelsplit_inputs[] = {
 
 AVFilter avfilter_af_channelsplit = {
     .name           = "channelsplit",
-    .description    = NULL_IF_CONFIG_SMALL("Split audio into per-channel streams"),
+    .description    = NULL_IF_CONFIG_SMALL("Split audio into per-channel streams."),
     .priv_size      = sizeof(ChannelSplitContext),
     .priv_class     = &channelsplit_class,
 

libavfilter/af_join.c

@@ -515,7 +515,7 @@ static const AVFilterPad avfilter_af_join_outputs[] = {
 AVFilter avfilter_af_join = {
     .name           = "join",
     .description    = NULL_IF_CONFIG_SMALL("Join multiple audio streams into "
-                                           "multi-channel output"),
+                                           "multi-channel output."),
     .priv_size      = sizeof(JoinContext),
     .priv_class     = &join_class,
 

libavfilter/vf_fieldmatch.c

@@ -974,7 +974,7 @@ static const AVFilterPad fieldmatch_outputs[] = {
 
 AVFilter avfilter_vf_fieldmatch = {
     .name           = "fieldmatch",
-    .description    = NULL_IF_CONFIG_SMALL("Field matching for inverse telecine"),
+    .description    = NULL_IF_CONFIG_SMALL("Field matching for inverse telecine."),
     .query_formats  = query_formats,
     .priv_size      = sizeof(FieldMatchContext),
     .init           = fieldmatch_init,

libavfilter/vf_fps.c

@@ -275,7 +275,7 @@ static const AVFilterPad avfilter_vf_fps_outputs[] = {
 
 AVFilter avfilter_vf_fps = {
     .name        = "fps",
-    .description = NULL_IF_CONFIG_SMALL("Force constant framerate"),
+    .description = NULL_IF_CONFIG_SMALL("Force constant framerate."),
 
     .init      = init,
     .uninit    = uninit,