HELP: updates from JSON generator and assorted cleanups

[hemostx]

• Refreshed alphabetical sorting of sections and keys for easier merging over time, keeping maintainers happy.

• The JSON generator is apparently case sensitive -> made HUD262 command descriptions lowercase so it doesn't introduce duplicates.

• Updated defaults in JSON from code: cl_chunksperframe 5 -> 30
  cl_demoplay_flash gets its 0.33 back
  joy* stuff defaults were missing
  r_fx_fog_density 0.002 -> 0.125
  scr_cursor_iconoffset_x 10 -> 0
  scr_teaminfo_show_countdown 0 -> 1
  vid_grab_keyboard 1->0
  vid_win_borderless did not mention its default value

• System-generated placeholders for dateiso, fs_savegame_home, vid_reload, vid_reload_auto (to be described)

• Updated some default cvar values according to actual behaviour: v_dlightcolor, v_dlightcshift, cl_bonusflash are actually used as bool/ints (no need to suggest a float value).

• Cleaned up palette spelling

• Fixed some grammar here and there

• Removed references to default values that aren't adding meaning to descriptions; ezq repeats defaults anyway.

• Same with some "on/off" descriptions adding nothing

• Simplified s_khz/s_linearresample. The latter is what actually gives perfect quality over s_khz, so made that clearer.

• s_linearresample_stream actually used in speex (VOIP) decoding, giving it a little description.

• rl_bloodcolor : r_explosiontype, not cl_

• r_skyname: help text does not use a "comments" field -> fixed to "remarks"

• Moved s_mixahead to legacy group.

• Moved some "descriptions" from "on/off" values to main desc (that's what it's for if that's all you'll write) cl_filterdrawviewmodel
  cl_model_bobbing
  cl_smartjump
  log_readable
  s_swapstereo
  scr_centermenu
  scr_centerbar
  scr_spectatorMessage
  tp_forcetriggers
  tp_loadlocs
  tp_msgtriggers

• Reworded log_readable
  scr_centerbar

• Removed old descriptions for LegacyCommands (help automatically redirects to the description for the new cvar) gl_smoothfont -> r_smoothtext
  scr_printspeed -> scr_centerspeed