fluent-bundle 0.15.0 (February 9, 2021)

• Document the crate.
• Update fluent-syntax to 0.11.0.
• Add iai benchmarks.
• Switch FluentArgs::add to FluentArgs::set.
• Make FluentArgs::set take Into<V>.
• Make FluentMessage and FluentAttribute fields use getters.
• Sort FluentArgs keys.
• Turn FluentMessage and FluentAttribute to be shallow wrappers around AST entries.