Fix clang build

[Siborgium]

Should fix #109

[jbeich]

Clang would've accepted [foo] -> [foo = foo] (capture by copy) as well:

--- a/grid/grid_tools.cc
+++ b/grid/grid_tools.cc
@@ -201,8 +201,8 @@ std::optional<DesktopEntry> desktop_entry(std::string&& path, const std::string&
             auto [ok, pos] = try_strip_prefix(prefix);
             if (ok) {
                 std::visit(visitor {
-                    [dest, pos, &view](nop_t) { *dest = view.substr(pos); },
-                    [dest, pos, &view](cut_t) {
+                    [dest = dest, pos = pos, &view](nop_t) { *dest = view.substr(pos); },
+                    [dest = dest, pos = pos, &view](cut_t) {
                         auto idx = view.find(" %", pos);
                         if (idx == std::string_view::npos) {
                             idx = std::size(view);

[Siborgium]

The issue with clang is not copying, it's that variables inside of structured bindings are not exactly variables. However, your solution is much cleaner. I'll use it in my local copy and hopefully merge into master with the next PR. Thanks!

[nwg-piotr]

@Siborgium do not forget to sync other PRs merged lately.