options: change --audio-file-auto default to not to load any files

There have been user complaints, and I'm annoyed by this behavior
myself.

DOCS/interface-changes.rst

@@ -45,6 +45,9 @@ Interface changes
       but changed to alias --loop-file
     - add --keep-open-pause=no
     - deprecate --demuxer-max-packets
+    - change --audio-file-auto default from "exact" to "no" (mpv won't load
+      files with the same filename as the video, but different extension, as
+      audio track anymore)
  --- mpv 0.24.0 ---
     - deprecate --hwdec-api and replace it with --opengl-hwdec-interop.
       The new option accepts both --hwdec values, as well as named backends.

options/options.c

@@ -933,7 +933,7 @@ const struct MPOpts mp_default_opts = {
     .movie_aspect = -1.,
     .field_dominance = -1,
     .sub_auto = 0,
-    .audiofile_auto = 0,
+    .audiofile_auto = -1,
     .osd_bar_visible = 1,
 #if HAVE_LIBASS
     .ass_enabled = 1,