manpage: update config file locations

Also add some explanations how the config paths are determined.

DOCS/encoding.rst

@@ -25,7 +25,7 @@ from the input video. Note that not all codecs and not all formats support VFR
 encoding, and some which do have bugs when a target bitrate is specified - use
 -ofps or -oautofps to force CFR encoding in these cases.
 
-Of course, the options can be stored in a profile, like this .mpv/config
+Of course, the options can be stored in a profile, like this .config/mpv/mpv.conf
 section::
 
   [myencprofile]

DOCS/man/mpv.rst

@@ -338,7 +338,7 @@ Location and Syntax
 You can put all of the options in configuration files which will be read every
 time mpv is run. The system-wide configuration file 'mpv.conf' is in your
 configuration directory (e.g. ``/etc/mpv`` or ``/usr/local/etc/mpv``), the
-user-specific one is ``~/.mpv/config``.
+user-specific one is ``~/.config/mpv/mpv.conf``.
 User-specific options override system-wide options and options given on the
 command line override either. The syntax of the configuration files is
 ``option=<value>``; everything after a *#* is considered a comment. Options
@@ -539,15 +539,23 @@ ENVIRONMENT VARIABLES
 There are a number of environment variables that can be used to control the
 behavior of mpv.
 
-``HOME``
-    Used to determine mpv config directory: ``$HOME/.mpv``
+``HOME``, ``XDG_CONFIG_HOME``
+    Used to determine mpv config directory. If ``XDG_CONFIG_HOME`` is not set,
+    ``$HOME/.config/mpv`` is used.
+
+    ``$HOME/.mpv`` is always added to the list of config search paths with a
+    lower priority.
+
+``XDG_CONFIG_DIRS``
+    If set, XDG-style system configuration directories are used. Otherwise,
+    the UNIX convention (``PREFIX/etc/mpv/``) is used.
 
 ``TERM``
     Used to determine terminal type.
 
 ``MPV_HOME``
     Directory where mpv looks for user settings. Overrides ``HOME``, and mpv
-    will try to load the config file as ``$MPV_HOME/config``.
+    will try to load the config file as ``$MPV_HOME/mpv.conf``.
 
 ``MPV_VERBOSE`` (see also ``-v`` and ``--msg-level``)
     Set the initial verbosity level across all message modules (default: 0).
@@ -660,18 +668,23 @@ FILES
 ``/usr/local/etc/mpv/mpv.conf``
     mpv system-wide settings (depends on ``--prefix`` passed to configure)
 
-``~/.mpv/config``
+``~/.config/mpv/mpv.conf``
     mpv user settings
 
-``~/.mpv/input.conf``
+``~/.config/mpv/input.conf``
     input bindings (see ``--input-keylist`` for the full list)
 
-``~/.mpv/lua/``
+``~/.config/mpv/lua/``
     All files in this directly are loaded as if they were passed to the
     ``--lua`` option. They are loaded in alphabetical order, and sub-directories
     and files with no ``.lua`` extension are ignored. The ``--load-scripts=no``
     option disables loading these files.
 
+Note that the environment variables ``$XDG_CONFIG_HOME`` and ``$MPV_HOME`` can
+override the standard directory ``~/.config/mpv/``.
+
+Also, the old config location at ``~/.mpv/`` is still read, and if the XDG
+variant does not exist, will still be preferred.
 
 EXAMPLES OF MPV USAGE
 =====================

DOCS/man/options.rst

@@ -1202,7 +1202,7 @@ OPTIONS
 
 ``--input-conf=<filename>``
     Specify input configuration file other than the default
-    ``~/.mpv/input.conf``.
+    ``~/.config/mpv/input.conf``.
 
 ``--no-input-default-bindings``
     Disable mpv default (builtin) key bindings.
@@ -1445,9 +1445,9 @@ OPTIONS
 
 ``--no-config``
     Do not load default configuration files. This prevents loading of
-    ``~/.mpv/config`` and ``~/.mpv/input.conf``, as well as loading the
-    same files from system wide configuration directories. Other configuration
-    files are blocked as well, such as resume playback files.
+    ``~/.config/mpv/mpv.conf`` and ``~/.config/mpv/input.conf``, as well as
+    loading the same files from system wide configuration directories. Other
+    configuration files are blocked as well, such as resume playback files.
 
     .. note::
 

etc/example.conf

@@ -2,7 +2,7 @@
 # mpv configuration file
 #
 # Configuration files are read system-wide from /usr/local/etc/mpv.conf
-# and per-user from ~/.mpv/config, where per-user settings override
+# and per-user from ~/.config/mpv/mpv.conf, where per-user settings override
 # system-wide settings, all of which are overridden by the command line.
 #
 # Configuration file settings and the command line options use the same

etc/input.conf

@@ -4,7 +4,7 @@
 # add new ones here.
 # See DOCS/man/input.rst for possible commands that can be bound.
 # Also see mpv --input-cmdlist for other possible options.
-# The file should be placed in the $HOME/.mpv directory.
+# The file should be placed in the $HOME/.config/mpv directory.
 #
 # mpv --input-test --force-window --idle can be used to test which commands
 # keys are bound to.
@@ -28,8 +28,8 @@
 # output drivers (not in output windows of other drivers or in a terminal).
 
 # All lines in this file are commented. If you want to remap a key, copy the
-# file to ~/.mpv/input.conf, and uncomment and edit the binding you want to
-# change.
+# file to ~/.config/mpv/input.conf, and uncomment and edit the binding you want
+# to change.
 
 # Developer note:
 # etc/input.conf from the mpv source tree is baked into the mpv binary, with