Inconsistent naming rules for field and template tags

[Toutouwai]

Short description of the issue

There are two ways to create a field tag: via Setup > Fields > Manage Tags and via Setup > Fields > [edit field] > Advanced > Tags

The naming allowed for tags in these two places are not consistent.

In Manage Tags I can create a tag containing uppercase characters:

If I then edit a field with that tag...

...and save it then the tag name is changed to all lowercase.

Expected behavior

Consistent naming rules for all places where a field/template tag can be created.

Setup/Environment

• ProcessWire version: 3.0.244