Fixes the OpenDyslexic extension readme

[olitreadwell]

About

Came across this readme today and wanted to help with a few fixes

Impacted Areas in Application

The application should not be impacted.

Only changes occurred within the README.

• Fixed the Chrome extension link
• Fixed the Firefox add on link
• Fixed the anchor tag href URL to go to the new .org website
• Fixed the path for the logo

[olitreadwell]

@antijingoist @RobertJGabriel

Made a few small fixes here.

A couple of questions (not addressed in this pull request):

1. I couldn't find a Microsoft Edge extension, should it be removed?
2. Would it be better to use <a> anchor tags for the links to allow them to open in a new tab?
3. Some folks use the GitHub in Dark mode all the time, so the OpenDyslexic logo is black font color on a dark background. Perhaps it would be better to use a non-transparent logo?

[RobertJGabriel]

Hey @olitreadwell

Looks great, thank you for the pull request.

Will get an OpenDyslexic on the Edge store this weekend.