obs-x264: Use period for localized sentence

plugins/obs-x264/data/locale/en-US.ini

@@ -10,4 +10,4 @@ Tune="Tune"
 None="(None)"
 EncoderOptions="x264 Options (separated by space)"
 VFR="Variable Framerate (VFR)"
-HdrUnsupported="OBS does not support using x264 with Rec. 2100"
+HdrUnsupported="OBS does not support using x264 with Rec. 2100."