"git ls-tree" does not support path selection based on negative
pathspecs, but did not error out when negative pathspecs are given.
* nd/ls-tree-pathspec:
t3102: style modernization
t3102: document that ls-tree does not yet support negated pathspec
ls-tree: disable negative pathspec because it's not supported
ls-tree: remove path filtering logic in show_tree
tree.c: update read_tree_recursive callback to pass strbuf as base