Removes shelltype option and all revelant doc. #1249

Fixes #1240

runtime/doc/change.txt

@@ -506,9 +506,9 @@ some text through a filter, so that it is replaced by the filter output.
 Examples of filters are "sort", which sorts lines alphabetically, and
 "indent", which formats C program files (you need a version of indent that
 works like a filter; not all versions do).  The 'shell' option specifies the
-shell Vim uses to execute the filter command (See also the 'shelltype'
-option).  You can repeat filter commands with ".".  Vim does not recognize a
-comment (starting with '"') after the `:!` command.
+shell Vim uses to execute the filter command.  You can repeat filter commands
+with ".".  Vim does not recognize a comment (starting with '"') after the
+`:!` command.
 
 							*!*
 !{motion}{filter}	Filter {motion} text lines through the external

runtime/doc/options.txt

@@ -6025,7 +6025,7 @@ A jump table for the options with a short description can be found at |Q_op|.
 					"cmd.exe", OS/2: "cmd")
 			global
 	Name of the shell to use for ! and :! commands.  When changing the
-	value also check these options: 'shelltype', 'shellpipe', 'shellslash'
+	value also check these options: 'shellpipe', 'shellslash'
 	'shellredir', 'shellquote', 'shellxquote' and 'shellcmdflag'.
 	It is allowed to give an argument to the command, e.g.  "csh -f".
 	See |option-backslash| about including spaces and backslashes.
@@ -6179,20 +6179,6 @@ A jump table for the options with a short description can be found at |Q_op|.
 	|FilterWritePost| autocommands event are not triggered when
 	'shelltemp' is off.
 
-						*'shelltype'* *'st'*
-'shelltype' 'st'	number	(default 0)
-			global
-			{not in Vi} {only for the Amiga}
-	On the Amiga this option influences the way how the commands work
-	which use a shell.
-	0 and 1: always use the shell
-	2 and 3: use the shell only to filter lines
-	4 and 5: use shell only for ':sh' command
-	When not using the shell, the command is executed directly.
-
-	0 and 2: use "shell 'shellcmdflag' cmd" to start external commands
-	1 and 3: use "shell cmd" to start external commands
-
 						*'shellxescape'* *'sxe'*
 'shellxescape' 'sxe'	string	(default: "";
 				 for MS-DOS and MS-Windows: "\"&|<>()@^")

runtime/doc/quickref.txt

@@ -856,7 +856,6 @@ Short explanation of each option:		*option-list*
 'shellredir'	  'srr'     string to put output of filter in a temp file
 'shellslash'	  'ssl'     use forward slash for shell file names
 'shelltemp'	  'stmp'    whether to use a temp file for shell commands
-'shelltype'	  'st'	    Amiga: influences how to use a shell
 'shellxescape'	  'sxe'     characters to escape when 'shellxquote' is (
 'shellxquote'	  'sxq'     like 'shellquote', but include redirection
 'shiftround'	  'sr'	    round indent to multiple of shiftwidth

runtime/doc/usr_10.txt

@@ -747,7 +747,6 @@ check the values of these options:
 	'shellcmdflag'	argument to pass a command to the shell
 	'shellquote'	quote to be used around the command
 	'shellxquote'	quote to be used around the command and redirection
-	'shelltype'	kind of shell (only for the Amiga)
 	'shellslash'	use forward slashes in the command (only for
 			MS-Windows and alikes)
 	'shellredir'	string used to write the command output into a file

runtime/doc/various.txt

@@ -232,8 +232,7 @@ g8			Print the hex values of the bytes used in the
 			mode.
 
 							*:!cmd* *:!* *E34*
-:!{cmd}			Execute {cmd} with the shell.  See also the 'shell'
-			and 'shelltype' option.
+:!{cmd}			Execute {cmd} with the shell. See also 'shell'.
 
 			Any '!' in {cmd} is replaced with the previous
 			external command (see also 'cpoptions').  But not when

runtime/doc/vi_diff.txt

@@ -620,9 +620,6 @@ all currently set marks.  The commands "']" and "`]" jump to the end of the
 previous operator or end of the text inserted with the put command.  "'[" and
 "`[" do jump to the start.
 
-The 'shelltype' option can be set to reflect the type of shell used on the
-Amiga.
-
 The 'highlight' option can be set for the highlight mode to be used for
 several commands.