style #12642 [Documentation] Fix Customizing API doc headers inconsistency (CoderMaggie)
style #12642 [Documentation] Fix Customizing API doc headers inconsistency (CoderMaggie)

This PR was merged into the 1.10-dev branch.

Discussion
----------

| Q               | A
| --------------- | -----
| Branch?         | master
| Doc fix?        | yes #12599 
| License         | MIT

Commits
-------

3e498bda858e7133a75c047b765f86c1899b9ce1 Fix Customizing API doc headers inconsistency

lchrusciel/Sylius,Zales0123/Sylius,SyliusBot/Sylius,pamil/Sylius,Zales0123/Sylius,101medialab/Sylius,lchrusciel/Sylius,pamil/Sylius,GSadee/Sylius,SyliusBot/Sylius,Arminek/Sylius,diimpp/Sylius,Arminek/Sylius,Zales0123/Sylius,101medialab/Sylius,antonioperic/Sylius,antonioperic/Sylius,Sylius/Sylius,GSadee/Sylius,lchrusciel/Sylius,diimpp/Sylius,diimpp/Sylius,pamil/Sylius,loic425/Sylius,loic425/Sylius,antonioperic/Sylius,Sylius/Sylius,loic425/Sylius,Sylius/Sylius,Arminek/Sylius,GSadee/Sylius,101medialab/Sylius,SyliusBot/Sylius