Chore: Help copy - Littlepay

[angela-tran]

Part of #1544

This PR updates the section explaining what Littlepay is. Reuses msgids from modal.

[machikoyasuda]

@angela-tran @srhhnry Is there a decided official style on whether the . comes before or after the external link arrow? I personally prefer the . comes after the external link arrow (even though the code is a little more annoying for that).

And should that same style apply to the modal question mark icon?

[srhhnry]

Yup, punctuation after the icon per the Styleguide (info on the desktop template under the Text Layout section).

It's been sort of difficult to portray that in Figma because the Google Sheets Sync doesn't interact with components (like the modal button, for instance), so I've added punctuation in manually where I see it, but any space adjustment or resync of the sheet can create spacing issues (:-/).

[srhhnry]

Also, just a heads up, punctuation after icon is based on USWDS: https://designsystem.digital.gov/components/link/

[angela-tran]

Sounds good @srhhnry , and thank you @machikoyasuda for asking for this to be clarified! I was going off the punctuation shown in the individual screens, but now I know to reference the Style Guide. I will fix

[angela-tran]

Dropped the commit that was solely for moving the period inside the link. Will open a separate PR to fix the other external link punctuation in the app