refactor #10344 [Docs] Update "Customizing Templates" (Tomanhez)
refactor #10344 [Docs] Update "Customizing Templates" (Tomanhez)

This PR was merged into the 1.3 branch.

Discussion
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| Q               | A
| --------------- | -----
| Branch?         | 1.3
| Bug fix?        | yes
| New feature?    | no
| BC breaks?      | no
| Deprecations?   | no
| License         | MIT

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Commits
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205c8ebbd626e9e8c5add0c5c4e9ab05d535ffda update customizing templates

antonioperic/Sylius,mbabker/Sylius,mbabker/Sylius,Sylius/Sylius,GSadee/Sylius,itinance/Sylius,pjedrzejewski/Sylius,antonioperic/Sylius,pjedrzejewski/Sylius,GSadee/Sylius,101medialab/Sylius,lchrusciel/Sylius,kayue/Sylius,kayue/Sylius,foobarflies/Sylius,foobarflies/Sylius,loic425/Sylius,antonioperic/Sylius,Arminek/Sylius,SyliusBot/Sylius,kayue/Sylius,foobarflies/Sylius,SyliusBot/Sylius,Brille24/Sylius,Brille24/Sylius,Arminek/Sylius,pamil/Sylius,foobarflies/Sylius,Sylius/Sylius,pjedrzejewski/Sylius,Brille24/Sylius,pamil/Sylius,Zales0123/Sylius,lchrusciel/Sylius,loic425/Sylius,lchrusciel/Sylius,itinance/Sylius,loic425/Sylius,itinance/Sylius,101medialab/Sylius,pamil/Sylius,itinance/Sylius,diimpp/Sylius,SyliusBot/Sylius,mbabker/Sylius,101medialab/Sylius,Zales0123/Sylius,Arminek/Sylius,pjedrzejewski/Sylius,GSadee/Sylius,diimpp/Sylius,Brille24/Sylius,diimpp/Sylius,mbabker/Sylius,Sylius/Sylius,Zales0123/Sylius