For users of globset who already have a `Vec<Glob>` (or similar),
the current API requires them to iterate over their `Vec<Glob>`,
calling `GlobSetBuilder::add` for each `Glob`, thus constructing a new
`Vec<Glob>` internal to the GlobSetBuilder. This makes the consuming
code unnecessarily verbose. (There is unlikely to be any meaningful
performance impact of this, however, since the cost of allocating a new
`Vec` is likely marginal compared to the cost of glob compilation.)
Instead of taking a `&[Glob]`, we accept an iterator of anything that
can be borrowed as a `&Glob`. This required some light refactoring of
the constructor, but nothing onerous.
Closes#3066
859d54270e