Branch needs to be updated

* added parameter weekday and thus ability to choose start day when using span in combination with frame == "week"

* changed default value for new parameter weekday.

* added test for new parameter weekday when using span and frame == "week"

* added comma after new parameter weekday.

* Update arrow/arrow.py

Co-authored-by: Chris <30196510+systemcatch@users.noreply.github.com>

* changed parameter name from weekday to week_start.

* extended doc string to highlight new parameter week_start.

* raise ValueError if 1 <= week_start <= 7 is not met

* renamed weekday to week_start in comment.

* changed if-else block to one liner. Updated comments.

* Update arrow/arrow.py

add blank line at the end of the docstring

Co-authored-by: Chris <30196510+systemcatch@users.noreply.github.com>

* Remove trailing whitespace

* added new line at end of doc string.

* Fix doc issue

* extended test_span_week by further test cases.

Co-authored-by: Jad Chaar <jadchaar@users.noreply.github.com>
Co-authored-by: Chris <30196510+systemcatch@users.noreply.github.com>
Co-authored-by: Jad Chaar <jad.chaar@gmail.com>

* Progress toward locale validation

* standardize and validate locales

* Add tests

* Clean up tests

* Use new locale name in error

* Remove useless comments

* Address comments

* English

* Remove default locale from test_parser

…put validation test cases. Implemented fixes as per discussion.

…put validation test cases. Implemented fixes as per discussion.