feat(eval/method): partially port v8.1.1993

Problem:    More functions can be used as methods.
Solution:   Make various functions usable as a method.
196b466443

server2client requires +clientserver, which hasn't been ported yet.
The eval.txt docs and test_clientserver.vim tests for server2client already exist, so include those
changes.

test_bufline.vim: Test for setbufline requires v8.1.1189 (which was reverted in #10848).

runtime/doc/eval.txt

@@ -5854,7 +5854,7 @@ histadd({history}, {item})				*histadd()*
 
 		Can also be used as a |method|, the base is used for the
 		second argument: >
-			GetPattern()->histadd('search')
+			GetHistory()->histadd('search')
 
 histdel({history} [, {item}])				*histdel()*
 		Clear {history}, i.e. delete all its entries.  See |hist-names|
@@ -8072,6 +8072,9 @@ screenattr({row}, {col})					*screenattr()*
 		arbitrary number that can only be used to compare to the
 		attribute at other positions.
 
+		Can also be used as a |method|: >
+			GetRow()->screenattr(col)
+
 screenchar({row}, {col})					*screenchar()*
 		The result is a Number, which is the character at position
 		[row, col] on the screen.  This works for every possible
@@ -8082,6 +8085,9 @@ screenchar({row}, {col})					*screenchar()*
 		This is mainly to be used for testing.
 		Returns -1 when row or col is out of range.
 
+		Can also be used as a |method|: >
+			GetRow()->screenchar(col)
+
 screenchars({row}, {col})					*screenchars()*
 		The result is a List of Numbers.  The first number is the same
 		as what |screenchar()| returns.  Further numbers are
@@ -8089,6 +8095,9 @@ screenchars({row}, {col})					*screenchars()*
 		This is mainly to be used for testing.
 		Returns an empty List when row or col is out of range.
 
+		Can also be used as a |method|: >
+			GetRow()->screenchars(col)
+
 screencol()							*screencol()*
 		The result is a Number, which is the current screen column of
 		the cursor. The leftmost column has number 1.
@@ -8124,6 +8133,9 @@ screenpos({winid}, {lnum}, {col})				*screenpos()*
  		right position and use |screencol()| to get the value with
  		|conceal| taken into account.
 
+		Can also be used as a |method|: >
+			GetWinid()->screenpos(lnum, col)
+
 screenrow()							*screenrow()*
 		The result is a Number, which is the current screen row of the
 		cursor.  The top line has number one.
@@ -8140,6 +8152,9 @@ screenstring({row}, {col})					*screenstring()*
 		This is mainly to be used for testing.
 		Returns an empty String when row or col is out of range.
 
+		Can also be used as a |method|: >
+			GetRow()->screenstring(col)
+
 search({pattern} [, {flags} [, {stopline} [, {timeout}]]])	*search()*
 		Search for regexp pattern {pattern}.  The search starts at the
 		cursor position (you can use |cursor()| to set it).
@@ -8230,6 +8245,8 @@ search({pattern} [, {flags} [, {stopline} [, {timeout}]]])	*search()*
 		without the 'e' flag if the cursor is on the "f" of "if".
 		The 'n' flag tells the function not to move the cursor.
 
+		Can also be used as a |method|: >
+			GetPattern()->search()
 
 searchcount([{options}])					*searchcount()*
 		Get or update the last search count, like what is displayed
@@ -8368,6 +8385,9 @@ searchdecl({name} [, {global} [, {thisblock}]])			*searchdecl()*
 			if searchdecl('myvar') == 0
 			   echo getline('.')
 			endif
+<
+		Can also be used as a |method|: >
+			GetName()->searchdecl()
 <
 							*searchpair()*
 searchpair({start}, {middle}, {end} [, {flags} [, {skip}
@@ -8483,6 +8503,9 @@ searchpos({pattern} [, {flags} [, {stopline} [, {timeout}]]])	*searchpos()*
 <		In this example "submatch" is 2 when a lowercase letter is
 		found |/\l|, 3 when an uppercase letter is found |/\u|.
 
+		Can also be used as a |method|: >
+			GetPattern()->searchpos()
+
 server2client({clientid}, {string})			*server2client()*
 		Send a reply string to {clientid}.  The most recent {clientid}
 		that sent a string can be retrieved with expand("<client>").
@@ -8494,6 +8517,9 @@ server2client({clientid}, {string})			*server2client()*
 		See also |clientserver|.
 		Example: >
 			:echo server2client(expand("<client>"), "HELLO")
+
+<		Can also be used as a |method|: >
+			GetClientId()->server2client(string)
 <
 serverlist()						*serverlist()*
 		Returns a list of server addresses, or empty if all servers
@@ -8559,6 +8585,9 @@ setbufline({buf}, {lnum}, {text})			*setbufline()*
 		If {buf} is not a valid buffer or {lnum} is not valid, an
 		error message is given.
 
+		Can also be used as a |method|: >
+			GetText()->setbufline(buf, lnum)
+
 setbufvar({buf}, {varname}, {val})			*setbufvar()*
 		Set option or local variable {varname} in buffer {buf} to
 		{val}.
@@ -8573,6 +8602,9 @@ setbufvar({buf}, {varname}, {val})			*setbufvar()*
 			:call setbufvar("todo", "myvar", "foobar")
 <		This function is not available in the |sandbox|.
 
+		Can also be used as a |method|: >
+			GetValue()->setbufvar(buf, varname)
+
 setcharsearch({dict})					*setcharsearch()*
 		Set the current character search information to {dict},
 		which contains one or more of the following entries:
@@ -8593,6 +8625,9 @@ setcharsearch({dict})					*setcharsearch()*
 			:call setcharsearch(prevsearch)
 <		Also see |getcharsearch()|.
 
+		Can also be used as a |method|: >
+			SavedSearch()->setcharsearch()
+
 setcmdpos({pos})					*setcmdpos()*
 		Set the cursor position in the command line to byte position
 		{pos}.  The first position is 1.
@@ -8608,6 +8643,9 @@ setcmdpos({pos})					*setcmdpos()*
 		Returns FALSE when successful, TRUE when not editing the
 		command line.
 
+		Can also be used as a |method|: >
+			GetPos()->setcmdpos()
+
 setenv({name}, {val})						*setenv()*
 		Set environment variable {name} to {val}.  Example: >
 			call setenv('HOME', '/home/myhome')
@@ -8615,6 +8653,9 @@ setenv({name}, {val})						*setenv()*
 <		When {val} is |v:null| the environment variable is deleted.
 		See also |expr-env|.
 
+		Can also be used as a |method|, passing the value as the base: >
+			GetPath()->setenv('PATH')
+
 setfperm({fname}, {mode})				*setfperm()* *chmod*
 		Set the file permissions for {fname} to {mode}.
 		{mode} must be a string with 9 characters.  It is of the form
@@ -8660,6 +8701,9 @@ setline({lnum}, {text})					*setline()*
 
 <		Note: The '[ and '] marks are not set.
 
+		Can also be used as a |method|, passing the text as the base: >
+			GetText()->setline(lnum)
+
 setloclist({nr}, {list}[, {action}[, {what}]])		*setloclist()*
 		Create or replace or add to the location list for window {nr}.
 		{nr} can be the window number or the |window-ID|.