runtime(doc): Fix wrong Mac default options

Clean up docs for macOS defaults. Simply use "Unix" across the board
instead of being inconsistent and occasionally using "Unix, macOS". Also
remove stale defaults that were erroneously renamed to "macOS" from
"Macintosh" when they were actually referring to Mac OS 9 which is no
longer supported.

runtime/doc/options.txt

@@ -3402,7 +3402,7 @@ A jump table for the options with a short description can be found at |Q_op|.
 
 					*'fileformat'* *'ff'*
 'fileformat' 'ff'	string (MS-Windows default: "dos",
-				Unix, macOS default: "unix")
+				Unix default: "unix")
 			local to buffer
 	This gives the <EOL> of the current buffer, which is used for
 	reading/writing the buffer from/to a file:
@@ -3425,7 +3425,7 @@ A jump table for the options with a short description can be found at |Q_op|.
 					*'fileformats'* *'ffs'*
 'fileformats' 'ffs'	string (default:
 				Vim+Vi	MS-Windows: "dos,unix",
-				Vim	Unix, macOS: "unix,dos",
+				Vim	Unix: "unix,dos",
 				Vi	Cygwin: "unix,dos",
 				Vi	others: "")
 			global
@@ -4916,7 +4916,7 @@ A jump table for the options with a short description can be found at |Q_op|.
 	set and to the Vim default value when 'compatible' is reset.
 
 						*'isprint'* *'isp'*
-'isprint' 'isp'	string	(default for Win32 and macOS:
+'isprint' 'isp'	string	(default for Win32 and VMS:
 				"@,~-255"; otherwise: "@,161-255")
 			global
 	The characters given by this option are displayed directly on the
@@ -6741,9 +6741,6 @@ A jump table for the options with a short description can be found at |Q_op|.
 						$VIMRUNTIME,
 						$VIM/vimfiles/after,
 						$HOME/vimfiles/after"
-					macOS: "$VIM:vimfiles,
-						$VIMRUNTIME,
-						$VIM:vimfiles:after"
 					Haiku: "$BE_USER_SETTINGS/vim,
 						$VIM/vimfiles,
 						$VIMRUNTIME,
@@ -9054,7 +9051,6 @@ A jump table for the options with a short description can be found at |Q_op|.
 					 for Win32: "$HOME/vimfiles/view",
 					 for Unix: "$HOME/.vim/view" or
 					           "$XDG_CONFIG_HOME/vim/view"
-					 for macOS: "$VIM/vimfiles/view",
 					 for VMS: "sys$login:vimfiles/view")
 			global
 			{not available when compiled without the |+mksession|