obs-ffmpeg: Fix bug on non-MSVC compilers

This happens because the enum had the incorrect name, and microsoft
automatically treats all enums as integers in C, regardless of whether
they actually exist or not.  Microsoft makes terrible compilers and
whoever decided this was a good idea should be fired.

plugins/obs-ffmpeg/obs-ffmpeg-source.c

@@ -45,7 +45,7 @@ struct ffmpeg_source {
 	enum AVPixelFormat sws_format;
 	uint8_t *sws_data;
 	int sws_linesize;
-	enum video_range range;
+	enum video_range_type range;
 	obs_source_t *source;
 
 	char *input;