What does this PR aim to accomplish?:

Based on pr #2508 and the issues based on it pi-hole/pi-hole#3063, a line of text is changed in the settings.php to inform the user that if changes are made dhcp leases are made, which is mentioned in the new note, to restart the FTL for the changes to take effect.

• I am aware that this change in v5 (which is just a text change) does not make sense since v6 will be released soon, but still I would like to use this PR to solve the problem mentioned above or complete the previous pull request mentioned above.

How does this PR accomplish the above?:

This pr simply appends a message in settings.php to inform users to run 'sudo service pihole-FTL restart' on their pihole if their devices are not issued the static IP address they have set.

Link documentation PRs if any are needed to support this PR:

I only added a simple text, so I don't think documentation is necessary.

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