lavc: rename h265 to hevc, add AV_CODEC_ID_H265 with identical value for backward compatibility

Somehow 2 different identifiers have come into existence which makes supporting
both until the next major version bump required
I did not investigate how exactly that did happen.

wm4, j-b and smarter prefer hevc.

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

libavcodec/codec_desc.c

@@ -226,9 +226,9 @@ static const AVCodecDescriptor codec_descriptors[] = {
         .props     = AV_CODEC_PROP_LOSSY | AV_CODEC_PROP_LOSSLESS,
     },
     {
-        .id        = AV_CODEC_ID_H265,
+        .id        = AV_CODEC_ID_HEVC,
         .type      = AVMEDIA_TYPE_VIDEO,
-        .name      = "h265",
+        .name      = "hevc",
         .long_name = NULL_IF_CONFIG_SMALL("H.265 / HEVC"),
         .props     = AV_CODEC_PROP_LOSSY | AV_CODEC_PROP_LOSSLESS,
     },