contrib : add naming guidelines (#11177)

contrib : add naming guidelines (#11177)

* contrib : add naming guidelines

* contrib : expand naming guidelines [no ci]

* contrib : cont [no ci]

* contrib : add `_t` suffix guideline [no ci]

* contrib : cont [no ci]

* minor [no ci]

* contrib : move coding guidelines to correct section [no ci]

* contrib : minor reword coding guidelines [no ci]

* contrib : add TODO for preprocessor directives [no ci]

* contrib : expand [no ci]

* minor [no ci]

* contrib : clarify `_context` suffix usage [no ci]

* contrib : filename guidelines [no ci]

* contrib : fix notes [no ci]