pangram: use collect() instead of from_iter() (#1034)
pangram: use collect() instead of from_iter() (#1034)

Same idea as https://github.com/exercism/rust/pull/1027 but for examples
not stubs.
exercism/xrust,petertseng/exercism-rust,exercism/xrust,petertseng/exercism-rust,petertseng/exercism-rust