fix: Adjust gist link address bar

[BeniCheni]

Fixes: #85

Use a single <input> for the gist link address bar:

• use Input with type=url
• remove placeholder to leverage on value for gist link
• update left padding style to look "okay"
• update related test snapshot.

(P.S.: These changes are based on my best "guesses". Happy to update according to review & advice. 🙏🏻)

Test

Test w. token population

[felixrieseberg]

Hey! Solid start, but there are a few issues here:

1. Typing results in the url being repeated over and over again
2. Would be nice to style the left side of the input box, too
3. The existing box has some nice url coercion that might break.

This really is a solid start though!

[BeniCheni]

Thank you, @felixrieseberg! I've updated accordingly. Please review again. 🙏
(Sorry about the delay. Been off the grid for other work stuff 📡. Now back to contribute to Electron Fiddle more "encore" 😸 )

1. Typing results in the url being repeated over and over again

Tested the original bug I introduced to understand more. Reverted to use the original placeholder attribute & its value.

2. Would be nice to style the left side of the input box, too

Inspected other input field's style more, & updated the style for the gist URL field's style.

3. The existing box has some nice url coercion that might break.

Read the regex in the gist.ts logic here, & used the pattern attribute to validate the pattern of the nice url coercion logic. Please definitely advise if my assumption is incorrect.

[felixrieseberg]

Hey @BeniCheni, good stuff! I found a few more small issues and decided to just fix them on your branch. I'm now just waiting to see if I broke any tests - if I didn't, I'll merge this later today!