Use `collections.Counter` instead of a `dict` in `terminal.py`

[Zac-HD]

Consider the following code defining counts, and the similar counts_by_filename below:

pytest/src/_pytest/terminal.py

Lines 757 to 760 in 95917f8

	counts: Dict[str, int] = {}
	for item in items:
	name = item.nodeid.split("::", 1)[0]
	counts[name] = counts.get(name, 0) + 1

This is a classic case for collections.Counter, and would make a great first pull request!

Example solution initialising the Counter from an iterable:

counts = Counter(... for item in items)  # you fill in the ... part

[tanvimehta]

Hello! I'm new to the open source community. Is this something I can pick up and work on?

[Zac-HD]

Absolutely! @-mention me from the PR and I'll be happy to review it for you 😃

[tanvimehta]

Great! Will do. Thanks!