Be more precise about escaping invalid characters in queries

[yubiuser]

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When FTL encounters invalid characters within a query, it will escape them with ~.
From the logging it was not clear which character was the replacement. This PR makes the logging more precise.

Example:

[2022-03-09 06:37:56.649 528M] INFO: FTL escaped 1 characters in "150.109.179.161Æz¡hÌz¡~ob¡"
[2022-03-09 06:37:56.676 528M] INFO: FTL escaped 1 characters in "150.109.179.161Æz¡hÌz¡~ob¡"
[2022-03-09 06:37:56.701 528M] INFO: FTL escaped 1 characters in "150.109.179.161Æz¡hÌz¡~ob¡"
[2022-03-09 06:37:56.719 528M] INFO: FTL escaped 1 characters in "150.109.179.161Æz¡hÌz¡~ob¡"

See this discourse thread: https://discourse.pi-hole.net/t/pihole-log-fill-up-with-strange-letter/54154

[DL6ER]

New output will be

[2022-03-09 06:37:56.649 528M] INFO: FTL replaced 1 invalid characters with ~ in the query "150.109.179.161Æz¡hÌz¡~ob¡"
[2022-03-09 06:37:56.676 528M] INFO: FTL replaced 1 invalid characters with ~ in the query "150.109.179.161Æz¡hÌz¡~ob¡"
[2022-03-09 06:37:56.701 528M] INFO: FTL replaced 1 invalid characters with ~ in the query "150.109.179.161Æz¡hÌz¡~ob¡"
[2022-03-09 06:37:56.719 528M] INFO: FTL replaced 1 invalid characters with ~ in the query "150.109.179.161Æz¡hÌz¡~ob¡"

[pralor-bot]

This pull request has been mentioned on Pi-hole Userspace. There might be relevant details there:

https://discourse.pi-hole.net/t/pi-hole-ftl-v5-15-web-v5-12-and-core-v5-10-released/54987/1