style/standardize mintlify capitalization

[Earnwithalee7890]

What changed? Why?
Capitalized "mintlify" to "Mintlify" in mintlify-reference.md when referring to the documentation platform.
Proper capitalization of product names ensures consistency and aligns with Mintlify's official branding.

Notes to reviewers

• Single-line change in the reference documentation file.
• Updated "Full mintlify reference docs..." to "Full Mintlify reference docs...".
• No functional changes, purely stylistic correction.

How has it been tested?

• Manual review of the file to confirm correct capitalization.
• Verified that the URL reference and other content remain unchanged.
• No impact on build or documentation rendering.

[cb-heimdall]

🟡 Heimdall Review Status

Requirement	Status	More Info
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