Updates to wording to match Chrome's messaging for managing search engines now.

Why is this change being made?

Author Checklist

• Provided a concise title for the MR
• Added a description to this MR explaining the reasons for the proposed change, per say-why-not-just-what
  • Sometime recently, Chrome updated their wording to say Manage Search Engines... instead of Edit Search Engines... so this change is to just to match our documentation match their browser wording along with the associated screenshot.
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