chore(docs): Updated pronouns as per style guide

[AlMilne]

Description

Updated pronouns in docs/docs/asset-prefix.md to match style guide:
Update pronouns in a doc to use "you" and "your" instead of "we" and "our"

Related Issues

#18284

[vladar]

Thank you so much for the PR!

[gatsbot]

Holy buckets, @AlMilne — we just merged your PR to Gatsby! 💪💜

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