PR: Add debug cell icon to the debug toolbar

[stevetracvc]

I recreated this after the CRLF PR

Description of Changes

I added the "Debug Cell" icon to the toolbar.

• Wrote at least one-line docstrings (for any new functions)
• Added unit test(s) covering the changes (if testable)

• Included a screenshot or animation (if affecting the UI, see Licecap)

Before

After

I find it extremely annoying that all of the major Debug tools are in the toolbar except for the Debug Cell tool. And sometimes, when trying to click on it from the Debug menu, I accidentally hit the "Run File" toolbar icon instead. This PR adds the icon, keeping the same ordering that is used in the Debug menu.

Affirmation

By submitting this Pull Request or typing my (user)name below,
I affirm the Developer Certificate of Origin
with respect to all commits and content included in this PR,
and understand I am releasing the same under Spyder's MIT (Expat) license.

I certify the above statement is true and correct: stevetracvc

[impact27]

looks good to me

[dalthviz]

Thanks @stevetracvc ! This LGTM 👍

However, just in case, could be worthy to do this over 5.x? What do you think @impact27 @ccordoba12 ?

If not, then I think we should proceed with this and merge 👍🏼

[impact27]

5.x sounds good to me

[stevetracvc]

@impact27 looks like @ccordoba12 did that too, switched back and forth immediately. Is there something I need to do to make it work with 5.x instead?

[dalthviz]

Yep @stevetracvc to move to 5.x this will need a rebase. For that I think the command is something like git rebase --onto 5.x master feat/debug-cell-toolbar (your 5.x branch should be up to date before doing this).

Also, sorry for all the hassle in order to land a one line change 😅. Hopefully after the rebase this could be merged without problem 🤞🏼

[stevetracvc]

hmmmmm I think the issue is the CRLF stuff again 🤣 hang on

[dalthviz]

Could it be better to just recreate this PR again but this time using as base branch 5.x for your feature branch locally @stevetracvc ?

[ccordoba12]

I'm not sure about adding this button to 5.x because it'd change the default interface and so it'd make harder for users to follow our docs.

So I'd say we should leave it for master (i.e. the future Spyder 6). That's something we agreed on with @impact27 already.

[dalthviz]

Then this LGTM 👍 Thanks @stevetracvc !