chore(docs): add the link for storing secrets to the Standard Library…

[NathanTarbert]

… section

close #6529

Checklist

• Title matches Winglang's style guide
• Description explains motivation and solution
• Tests added (always)
• Docs updated (only required for features)
• Added pr/e2e-full label if this feature requires end-to-end testing

By submitting this pull request, I confirm that my contribution is made under the terms of the Wing Cloud Contribution License.

[github-actions]

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Topic	Owner
Wing SDK and utility APIs	@chriscbr
Wing Console	@ainvoner, @skyrpex, @polamoros
JSON, structs, primitives and collections	@hasanaburayyan
Platforms and plugins	@hasanaburayyan
Frontend resources (website, react, etc)	@tsuf239
Language design	@chriscbr
VSCode extension and language server	@markmcculloh
Compiler architecture, inflights, lifting	@yoav-steinberg
Wing Testing Framework	@tsuf239
Wing CLI	@markmcculloh
Build system, dev environment, releases	@markmcculloh
Library Ecosystem	@chriscbr
Documentation	@hasanaburayyan
SDK test suite	@tsuf239
Examples	@hasanaburayyan
Wing Playground	@eladcon

[monadabot]

Congrats! 🚀 This was released in Wing 0.74.50.