Allow an unterminated pattern after earlier address parts

A field holding a tab arrives cut short, so :BTags with 'ctags
--excmd=combine' sees '2;/^int tabbed(void) {' and stopped jumping. The last
part runs to the end of the line, taking any '|' or ';' with it, so it still
cannot chain a command.

autoload/fzf/vim.vim

@@ -543,9 +543,10 @@ endfunction
 " Address of a tag, given the rest of the line after the file name. Only the
 " forms a tags file is meant to hold, a line number and a search pattern,
 " chained with ';' for '--excmd=combine' and cut at the ';"' terminator as
-" Vim's find_extra() does. A pattern left unterminated runs to the end of the
+" Vim's find_extra() does. The last pattern can be left unterminated, as a
-" line, taking any '|' or ';' with it, so it cannot chain a command. Returns
+" field holding a tab arrives cut short; it then runs to the end of the line,
-" an empty string for anything else, which is then not run.
+" taking any '|' or ';' with it, so it cannot chain a command. Returns an
+" empty string for anything else, which is then not run.
 let s:tag_address_part = '\%(\d\+\|/\%(\\.\|[^/\\]\)*/\|?\%(\\.\|[^?\\]\)*?\)'
 let s:tag_address_open = '\%(/\%(\\.\|[^/\\]\)*\|?\%(\\.\|[^?\\]\)*\)'
 function! s:tag_address(rest)
@@ -553,7 +554,8 @@ function! s:tag_address(rest)
   let rest = s:strip(a:rest)
   let address = matchstr(rest,
         \ '^'.s:tag_address_part.'\%(;'.s:tag_address_part.'\)*\ze\%(;"\|$\)')
-  return empty(address) ? matchstr(rest, '^'.s:tag_address_open.'$') : address
+  return empty(address) ? matchstr(rest,
+        \ '^\%('.s:tag_address_part.';\)*'.s:tag_address_open.'$') : address
 endfunction
 
 " [key, [filename, [stay_on_edit: 0]]]