Misc doc changes

[kianmeng]

List of changes

• Fix typo
• Add changelog to html doc
• Add changelog link to hex info page
• Use common source url

[coveralls]

Pull Request Test Coverage Report for Build b60f8536dd0deb69f21ec7778150e35734014c76-PR-88

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 76.0%

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Totals
Change from base Build 47ec99bb8fc60cbf81204c790fd19807b330571f:	0.0%
Covered Lines:	133
Relevant Lines:	175

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💛 - Coveralls

[whatyouhide]

Thanks @kianmeng! 💟