patch 8.2.0861: cannot easily get all the current marks

Problem:    Cannot easily get all the current marks.
Solution:   Add getmarklist(). (Yegappan Lakshmanan, closes #6032)

runtime/doc/eval.txt

@@ -2497,6 +2497,7 @@ getjumplist([{winnr} [, {tabnr}]])
 getline({lnum})			String	line {lnum} of current buffer
 getline({lnum}, {end})		List	lines {lnum} to {end} of current buffer
 getloclist({nr} [, {what}])	List	list of location list items
+getmarklist([{expr}])		List	list of global/local marks
 getmatches([{win}])		List	list of current matches
 getmousepos()			Dict	last known mouse position
 getpid()			Number	process ID of Vim
@@ -5365,6 +5366,25 @@ getloclist({nr} [, {what}])				*getloclist()*
 					|location-list-file-window| for more
 					details.
 
+getmarklist([{expr}]					*getmarklist()*
+		Without the {expr} argument returns a |List| with information
+		about all the global marks. |mark|
+
+		If the optional {expr} argument is specified, returns the
+		local marks defined in buffer {expr}.  For the use of {expr},
+		see |bufname()|.
+
+		Each item in the retuned List is a |Dict| with the following:
+		    name - name of the mark prefixed by "'"
+		    pos - a |List| with the position of the mark:
+				[bufnum, lnum, col, off]
+			  Refer to |getpos()| for more information.
+		    file - file name
+
+		Refer to |getpos()| for getting information about a specific
+		mark.
+
+
 getmatches([{win}])					*getmatches()*
 		Returns a |List| with all matches previously defined for the
 		current window by |matchadd()| and the |:match| commands.

runtime/doc/usr_41.txt

@@ -724,6 +724,7 @@ Cursor and mark position:		*cursor-functions* *mark-functions*
 	getcurpos()		get position of the cursor
 	getpos()		get position of cursor, mark, etc.
 	setpos()		set position of cursor, mark, etc.
+	getmarklist()		list of global/local marks
 	byte2line()		get line number at a specific byte count
 	line2byte()		byte count at a specific line
 	diff_filler()		get the number of filler lines above a line