tree bd8b286bc73da1faad6693fd6b79e251ffcfa184
parent 9e875938052443c7f51b25012093be59e20598ac
author QUICHE team <quiche-dev@google.com> 1708111669 -0800
committer Copybara-Service <copybara-worker@google.com> 1708111719 -0800

Add find and clear methods to structured-header Dictionary type

- Precedent in [`std::map::find`](https://en.cppreference.com/w/cpp/container/map/find)
- Reimplement other indexing methods using `find`
- Explicitly default move constructor and move-assign operator

PiperOrigin-RevId: 607749355