Fix/accessibility link text base account

[Earnwithalee7890]

What changed? Why?
Refined link text in the Base Account documentation to improve accessibility. Replaced uninformative anchors like "here" with descriptive labels to assist users relying on screen readers.

Notes to reviewers

• Updates were applied to migration-guide.mdx and basenames-faq.mdx.
• Focus was on ensuring the link text clearly describes the referenced content (e.g., "See the migration guide" instead of "Click here").

How has it been tested?

• Validated markdown rendering to ensure links are functional and text flows logically.

[cb-heimdall]

🟡 Heimdall Review Status

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Reviews	🟡 0/2	Denominator calculation Show calculation 1 if user is bot 0 1 if user is external 0 2 if repo is sensitive 0 From .codeflow.yml 1 Additional review requirements Show calculation Max 0 0 From CODEOWNERS 0 Global minimum 0 Max 1 1 1 if commit is unverified 1 Sum 2