New gutter setting

[SuDa2103]

• Updated GitLive Settings Screenshots in Privacy Section
• New paragraph and screenshot at the end to show people how to turn off gutter indicators in their GitLive settings

[github-actions[bot]]

Visit the preview URL for this PR (updated for commit cb00133):

https://gitlive-docs--pr43-new-gutter-setting-s5nhh043.web.app

_{(expires Tue, 23 Mar 2021 17:00:29 GMT)}

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