Peter M. Groen / CLI11

* chore: update clang-tidy

Signed-off-by: Henry Schreiner <henryschreineriii@gmail.com>

* refactor: address clang-tidy

* fix: C++11 support

Signed-off-by: Henry Schreiner <henryschreineriii@gmail.com>

* chore: two more clang-tidy fixes

Signed-off-by: Henry Schreiner <henryschreineriii@gmail.com>

* fix: get_inject_separator should be bool

* refactor: addressing review feedback

Signed-off-by: Henry Schreiner <henryschreineriii@gmail.com>
Co-authored-by: Philip Top <phlptp@gmail.com>

* Apply suggestions from code review

* Update include/CLI/Config.hpp

* Update include/CLI/Config.hpp

* Update include/CLI/Config.hpp

* Update include/CLI/Config.hpp

Co-authored-by: Philip Top <phlptp@gmail.com>

* Fix a potential stack overflow error if nameless subcommands have fallthough

* style: pre-commit.ci fixes

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>