Fix added lines not being checked

Need to account for `a:added` in the listener when checking which lines
had trailing whitespace added to them, since the range `a:start` to
`a:end` is in the context of before the change.

Author: axelf4

plugin/strip_trailing_whitespace.vim

@@ -204,7 +204,7 @@ function StripTrailingWhitespaceListener(bufnr, start, end, added, changes) abor
 	endif
 
 	" (Re-)Add lines in range with trailing whitespace
-	for lnum in range(a:start, a:end - 1)
+	for lnum in range(a:start, a:end + a:added - 1)
 		let has_trailing_ws = getline(lnum) =~# '\s$'
 		if has_trailing_ws
 			call s:Put(lnum)

test/test.vim

@@ -27,6 +27,13 @@ function Test_AddLineAboveChange() abort
 	call s:TestEdits(['foo '], function('s:EditCb'), ['', 'zoo'])
 endfunction
 
+function Test_DeleteAndPut() abort
+	function! s:EditCb() abort
+		normal! j2ddP
+	endfunction
+	call s:TestEdits(['first ', 'second ', 'third ', 'forth '], function('s:EditCb'), ['first ', 'second', 'third', 'forth '])
+endfunction
+
 function Test_AbleToDisable() abort
 	function! s:EditCb() abort
 		let b:strip_trailing_whitespace_enabled = 0