Add missing quotes (by ExolonDX)

Apply this syntax fix to 2.1 branch (already applied in main after 2.1 was branched - https://github.com/pfsense/pfsense/commit/c620c1817e49f8afa4078e342e0f4b4e111a7ef5)
Deprecate ampersand (by ExolonDX)

Apply this syntax fix to 2.1 branch (already applied in main after 2.1 was branched - https://github.com/pfsense/pfsense/commit/4cafb367f136489a534d7b3a4ba49c2ed8f6df08 )
Merge pull request #657 from phil-davis/RELENG_2_1

Minor PHP syntax fixes from ExolonDX