Chore: Typo fixed in multiple files

[SusheelThapa]

This PR fix the typo in multiple files

Thes > The
JavasSript > JavaScript
benefitial > beneficial
Alternativey > Alternatively

Please check the following:

• Do the tests still pass?¹
• Does the code comply with the style guide?
  • Run make lint from the Wagtail root.
• For Python changes: Have you added tests to cover the new/fixed behaviour?
• For front-end changes: Did you test on all of Wagtail’s supported environments?²
  • Please list the exact browser and operating system versions you tested:
  • Please list which assistive technologies ³ you tested:
• For new features: Has the documentation been updated accordingly?

Please describe additional details for testing this change.

Footnotes

1. Development Testing ↩

2. Browser and device support ↩

3. Accessibility Target ↩

[squash-labs]

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Test this branch here: https://susheelthapapatch-xmqja.squash.io

[lb-]

Great, thank you, this looks good - I have just reverted that one small item.

[lb-]

Thank you @SusheelThapa - I have added you to the contributor's list as 'Susheel Thapa' let me know if you wanted a different name listed.