Conf.example: Move some lines to minetest.conf.example.extra

Some information in conf.example cannot be generated from
settingtypes.txt, moving it to a new file makes generating
conf.example while preserving that information easier.

Regenerate conf.example from settingtypes.txt.

minetest.conf.example

@@ -92,7 +92,7 @@
 # joystick_id = 0
 
 #    The type of joystick
-#    type: enum values: auto,generic,xbox
+#    type: enum values: auto, generic, xbox
 # joystick_type = auto
 
 #    The time in seconds it takes between repeated events
@@ -1201,25 +1201,6 @@
 #    type: int
 # num_emerge_threads = 1
 
-#### Noise parameters and formats
-
-#    Noise parameters can be specified as a set of positional values, for example:
-#    Offset, scale, (spread factors), seed offset, number of octaves, persistence, lacunarity
-# mgv6_np_terrain_base = -4, 20, (250, 250, 250), 82341, 5, 0.6, 2.0
-#    Or the group format can be used instead, for example:
-# mgv6_np_terrain_base = {
-#    offset      = -4,
-#    scale       = 20,
-#    spread      = (250, 250, 250),
-#    seed        = 82341,
-#    octaves     = 5,
-#    persistence = 0.6,
-#    lacunarity  = 2.0,
-#    flags       = "defaults"
-# }
-#    Only the group format supports noise flags which are needed for eased noise.
-#    Mgv5 uses eased noise for np_ground so this is shown in group format below.
-
 #### Biome API temperature and humidity noise parameters
 
 #    Temperature variation for biomes.
@@ -1287,22 +1268,6 @@
 #    type: noise_params
 # mgv5_np_cavern = 0, 1, (384, 128, 384), 723, 5, 0.63, 2.0
 
-#    Noise parameter in group format, unsupported by advanced settings
-#    menu but settable in minetest.conf.
-#    See documentation of noise parameter formats above.
-#    3D noise defining terrain.
-#    type: noise_params
-# mgv5_np_ground = {
-#    offset      = 0,
-#    scale       = 40,
-#    spread      = (80, 80, 80),
-#    seed        = 983240,
-#    octaves     = 4,
-#    persistence = 0.55,
-#    lacunarity  = 2.0,
-#    flags       = "eased"
-# }
-
 #### Mapgen v6
 
 #    Map generation attributes specific to Mapgen v6.