Update adding-a-magic-string-format-function.md

[prjseal]

remove duplicate word the

Description

I simply removed a duplicate word, the

Type of suggestion

• Typo/grammar fix
• Updated outdated content
• New content
• Updates related to a new version
• Other

Product & version (if relevant)

Deadline (if relevant)

Whenever you wish

[alina-tincas]

Hi @prjseal thank you for the PR 🙌

We will take a look at it as soon as we can 😊

[eshanrnh]

Thanks for catching the duplicate word and updating it, @prjseal 🙌

I've updated the 13 and 12 versions too to reflect the change 💪