Improves a sentence in guides/security

Changed "... books make this wrong" to "... books get this wrong"
Merge pull request #12167 from hannesfostie/grammar-improvement

[ci skip] Improves a sentence in guides/security
Remove BasicRendering and remove template functionality from AbsC::Rendering
Remove remaining coupling with AV in MimeResponds
Remove BasicRendering tests
Remove helper fixtures not used in any test

The fixture for module AbcHelper defines three functions bare_a,
bare_b and bare_c, but only bare_a is used in the code that tests
helper functions.
stop using deprecated api in the tests
make @bitsweat happy. :heart:
let the class cache object clean up user input
Merge pull request #12181 from claudiob/remove-unused-helper-fixtures

Remove helper fixtures not used in any test
Removed unnecessary require
Removed unused modules and classes
Merge pull request #12187 from anupamc/master

Removed unnecessary require