lsp+fzf preview show incorrect line.

[lzh01]

In code https://github.com/liuchengxu/vista.vim/blob/f925e481bba7cd5451fb8bca9a6ecfc2bf1f2858/autoload/vista/finder.vim#L158-L193

It all depends on ':' as field separator, but when 'symbol' name or the line of code contains ':', the fzf preview can't get the correct line, will mostly end up showing from the start of the file.

For example, it can't handle lsp result line like

ClassA::varName:250 Variable yyy = "asdf:asdf";
function:275 Function ClassA::function() {

Tried to fix, but seems we have to use a different separator like '|' for the input.