patch 8.1.1954: more functions can be used as a method

Problem:    More functions can be used as a method.
Solution:   Allow more functions to be used as a method.

runtime/doc/eval.txt

@@ -1228,7 +1228,7 @@ next method: >
 	mylist->filter(filterexpr)->map(mapexpr)->sort()->join()
 <
 Example of using a lambda: >
-	GetPercentage->{x -> x * 100}()->printf('%d%%')
+	GetPercentage()->{x -> x * 100}()->printf('%d%%')
 <
 When using -> the |expr7| operators will be applied first, thus: >
 	-1.234->string()
@@ -6206,6 +6206,9 @@ js_decode({string})					*js_decode()*
 		- Empty items in an array (between two commas) are allowed and
 		  result in v:none items.
 
+		Can also be used as a |method|: >
+			ReadObject()->js_decode()
+
 js_encode({expr})					*js_encode()*
 		This is similar to |json_encode()| with these differences:
 		- Object key names are not in quotes.
@@ -6220,6 +6223,8 @@ js_encode({expr})					*js_encode()*
 		This encoding is valid for JavaScript. It is more efficient
 		than JSON, especially when using an array with optional items.
 
+		Can also be used as a |method|: >
+			GetObject()->js_encode()
 
 json_decode({string})					*json_decode()*
 		This parses a JSON formatted string and returns the equivalent
@@ -6254,6 +6259,8 @@ json_decode({string})					*json_decode()*
 		accepted by json_decode() as the result must be a valid Vim
 		type, e.g. this fails: {"a":"b", "a":"c"}
 
+		Can also be used as a |method|: >
+			ReadObject()->json_decode()
 
 json_encode({expr})					*json_encode()*
 		Encode {expr} as JSON and return this as a string.
@@ -6280,6 +6287,9 @@ json_encode({expr})					*json_encode()*
 		missing in the JSON standard, but several implementations do
 		allow it.  If not then you will get an error.
 
+		Can also be used as a |method|: >
+			GetObject()->json_encode()
+
 keys({dict})						*keys()*
 		Return a |List| with all the keys of {dict}.  The |List| is in
 		arbitrary order.  Also see |items()| and |values()|.
@@ -6346,6 +6356,10 @@ libcall({libname}, {funcname}, {argument})
 		feature is present}
 		Examples: >
 			:echo libcall("libc.so", "getenv", "HOME")
+
+<		Can also be used as a |method|, where the base is passed as
+		the argument to the called function: >
+			GetValue()->libcall("libc.so", "getenv")
 <
 							*libcallnr()*
 libcallnr({libname}, {funcname}, {argument})
@@ -6357,6 +6371,10 @@ libcallnr({libname}, {funcname}, {argument})
 			:echo libcallnr("/usr/lib/libc.so", "getpid", "")
 			:call libcallnr("libc.so", "printf", "Hello World!\n")
 			:call libcallnr("libc.so", "sleep", 10)
+<
+		Can also be used as a |method|, where the base is passed as
+		the argument to the called function: >
+			GetValue()->libcallnr("libc.so", "printf")
 <
 							*line()*
 line({expr})	The result is a Number, which is the line number of the file
@@ -6385,6 +6403,9 @@ line({expr})	The result is a Number, which is the line number of the file
 		To jump to the last known position when opening a file see
 		|last-position-jump|.
 
+		Can also be used as a |method|: >
+			GetValue()->line()
+
 line2byte({lnum})					*line2byte()*
 		Return the byte count from the start of the buffer for line
 		{lnum}.  This includes the end-of-line character, depending on
@@ -6399,6 +6420,9 @@ line2byte({lnum})					*line2byte()*
 		disabled at compile time, -1 is returned.
 		Also see |byte2line()|, |go| and |:goto|.
 
+		Can also be used as a |method|: >
+			GetLnum()->line2byte()
+
 lispindent({lnum})					*lispindent()*
 		Get the amount of indent for line {lnum} according the lisp
 		indenting rules, as with 'lisp'.
@@ -6407,6 +6431,9 @@ lispindent({lnum})					*lispindent()*
 		When {lnum} is invalid or Vim was not compiled the
 		|+lispindent| feature, -1 is returned.
 
+		Can also be used as a |method|: >
+			GetLnum()->lispindent()
+
 list2str({list} [, {utf8}])				*list2str()*
 		Convert each number in {list} to a character string can
 		concatenate them all.  Examples: >
@@ -6421,6 +6448,9 @@ list2str({list} [, {utf8}])				*list2str()*
 		With utf-8 composing characters work as expected: >
 			list2str([97, 769])	returns "á"
 <
+		Can also be used as a |method|: >
+			GetList()->list2str()
+
 listener_add({callback} [, {buf}])			*listener_add()*
 		Add a callback function that will be invoked when changes have
 		been made to buffer {buf}.
@@ -6490,6 +6520,10 @@ listener_add({callback} [, {buf}])			*listener_add()*
 		The {callback} is also not invoked when the buffer is
 		unloaded, use the |BufUnload| autocmd event for that.
 
+		Can also be used as a |method|, where the base is passed as
+		the second argument, the buffer: >
+			GetBuffer()->listener_add(callback)
+
 listener_flush([{buf}])					*listener_flush()*
 		Invoke listener callbacks for buffer {buf}.  If there are no
 		pending changes then no callbacks are invoked.
@@ -6498,11 +6532,17 @@ listener_flush([{buf}])					*listener_flush()*
 		values, see |bufname()|.  When {buf} is omitted the current
 		buffer is used.
 
+		Can also be used as a |method|: >
+			GetBuffer()->listener_flush()
+
 listener_remove({id})					*listener_remove()*
 		Remove a listener previously added with listener_add().
 		Returns zero when {id} could not be found, one when {id} was
 		removed.
 
+		Can also be used as a |method|: >
+			GetListenerId()->listener_remove()
+
 localtime()						*localtime()*
 		Return the current time, measured as seconds since 1st Jan
 		1970.  See also |strftime()| and |getftime()|.
@@ -6550,7 +6590,11 @@ luaeval({expr} [, {expr}])					*luaeval()*
 		as-is.
 		Other objects are returned as zero without any errors.
 		See |lua-luaeval| for more details.
-		{only available when compiled with the |+lua| feature}
+
+		Can also be used as a |method|: >
+			GetExpr()->luaeval()
+
+<		{only available when compiled with the |+lua| feature}
 
 map({expr1}, {expr2})					*map()*
 		{expr1} must be a |List| or a |Dictionary|.