Remove 'antialias' remnants

It never did anything (see `:h hidden-options`).

runtime/doc/options.txt

@@ -643,17 +643,6 @@ A jump table for the options with a short description can be found at |Q_op|.
 	compiled with the |+termresponse| feature and if |t_u7| is set to the
 	escape sequence to request cursor position report.
 
-			*'antialias'* *'anti'* *'noantialias'* *'noanti'*
-'antialias' 'anti'	boolean (default: off)
-			global
-			{only available when compiled with GUI enabled
-			on Mac OS X}
-	This option only has an effect in the GUI version of Vim on Mac OS X
-	v10.2 or later.  When on, Vim will use smooth ("antialiased") fonts,
-	which can be easier to read at certain sizes on certain displays.
-	Setting this option can sometimes cause problems if 'guifont' is set
-	to its default (empty string).
-
 			*'autochdir'* *'acd'* *'noautochdir'* *'noacd'*
 'autochdir' 'acd'	boolean (default off)
 			global

runtime/doc/quickref.txt

@@ -600,7 +600,6 @@ Short explanation of each option:		*option-list*
 'allowrevins'	  'ari'     allow CTRL-_ in Insert and Command-line mode
 'altkeymap'	  'akm'     for default second language (Farsi/Hebrew)
 'ambiwidth'	  'ambw'    what to do with Unicode chars of ambiguous width
-'antialias'	  'anti'    Mac OS X: use smooth, antialiased fonts
 'autochdir'	  'acd'     change directory to the file in the current window
 'arabic'	  'arab'    for Arabic as a default second language
 'arabicshape'	  'arshape' do shaping for Arabic characters

runtime/doc/vim_diff.txt

@@ -195,6 +195,7 @@ Highlight groups:
   |hl-VisualNOS|
 
 Other options:
+  'antialias'
   'cpoptions' ('g', 'w', 'H', '*', '-', 'j', and all POSIX flags were removed)
   'guioptions' (only the 't' flag was removed)
   'guipty'

runtime/optwin.vim

@@ -576,10 +576,6 @@ if has("gui")
   endif
   call append("$", "guifontwide\tlist of font names to be used for double-wide characters")
   call <SID>OptionG("gfw", &gfw)
-  if has("mac")
-    call append("$", "antialias\tuse smooth, antialiased fonts")
-    call <SID>BinOptionG("anti", &anti)
-  endif
   call append("$", "guioptions\tlist of flags that specify how the GUI works")
   call <SID>OptionG("go", &go)
   if has("gui_gtk")

src/nvim/options.lua

@@ -50,15 +50,6 @@ return {
       varname='p_aleph',
       defaults={if_true={vi=224}}
     },
-    {
-      full_name='antialias', abbreviation='anti',
-      type='bool', scope={'global'},
-      vi_def=true,
-      vim=true,
-      redraw={'everything'},
-      enable_if=false,
-      defaults={if_true={vi=false, vim=false}}
-    },
     {
       full_name='arabic', abbreviation='arab',
       type='bool', scope={'window'},