Shortcut for toggling multi-line comments

[marcospb19]

As an example, in Rust, I'd like to press Ctrl+Shift+/ to put /**/ surrounding my selection.

This also fits well with multi-cursors.

// Get the references in ascending order
let refs = [
    /* 0 */ &tree,
    /* 1 */ &tree[".config/"],
    /* 2 */ &tree[".config/i3/"],
    /* 5 */ &tree[".config/i3/dir/"],
    /* 6 */ &tree[".config/i3/dir/innerfile1"],
    /* 7 */ &tree[".config/i3/dir/innerfile2"],
    /* 3 */ &tree[".config/i3/file1"],
    /* 4 */ &tree[".config/i3/file2"],
    /* 8 */ &tree[".config/i3/file3"],
    /* 9 */ &tree[".config/outerfile1"],
    /* 0 */ &tree[".config/outerfile2"],
];