fix(javascript-calculator): adjust minus unicode, add noreferrer

[Dave2188]

Checklist:

• [ x] I have read freeCodeCamp's contribution guidelines.
• [x ] My pull request has a descriptive title (not a vague title like Update index.md)

Partially addresses #49045

I included the closing number for issue 49045 because while working on it, I could not replicate that specific issue. In the process, I discovered that the minus operator was showing as a zero. I changed the character based on the warning and has seemed to fix the issue.

Also was receiving a warning due to missing rel-tag, so I included that as well.

[ShaunSHamilton]

Thank you for taking the time to contribute.

I am happy with this change. I also see the warning about the uncommon unicode character. However, I do not see a 0 in place of it on the production app.

How/where did you get the 301 = 2?

[Dave2188]

Every time I would hit the minus key a zero would appear on the calculator. The functionality was working correctly. The only thing I could think of was that it was having trouble with the character. I'm on a mac with chrome if that could be playing a part.

[scissorsneedfoodtoo]

Thank you for taking the time to investigate this issue and for these fixes, @Dave2188.

I can replicate this on my Mac running Chrome, where 9-3=6 appears as 903=6:

Firefox doesn't have the same issue, and the - operator is displayed correctly.

The fixes here seem to do the trick. Here are some screenshots from Chrome on my Mac after the fixes:

About freeCodeCamp/freeCodeCamp#49045, your fixes might just partially address the issue detailed there. From the comments it looks like some people might have had the - operator replaced by 0.

I'm still able to reproduce the specific issue there, where +0+0+0+0+0+0+-1 = -1 is displayed as --1 = -1. Though strangely it only happens if +0 appears 6 or more times. Less than 6 times and everything is displayed properly.

I think we can accept this as an improvement for people running Chrome / Chromium on Macs, and leave that issue open in case someone comes up with a fix.

[Dave2188]

I found the fix to the last issue discussed above and another around when you minus a number by a negative number. Should push it to this branch or create a new one for checking?

[Dave2188]

@scissorsneedfoodtoo These are some shots of the output after entering +0+0+0+0+0+0+0+-1, which now displays correctly, and 9 - -9 before displayed 18 and now displays correctly with 0.

[ShaunSHamilton]

Thank you for all your work on this 👍

[naomi-lgbt]

Changes deployed!