Fix og url and add overrides

[prrao87]

• Fix URL for og image
• Move the blog url to external link within header
• Fix broken links

[prrao87]

@mewim I'd like to make the blog URL on the header look like below (from what I've seen in other blogs), so that it's obvious to the user that it's an external link that takes them out of the docs. An example from here is shown below.

Would you be able to make the updates to include this icon? The code that overrides the default header is here.

[mewim]

@mewim I'd like to make the blog URL on the header look like below (from what I've seen in other blogs), so that it's obvious to the user that it's an external link that takes them out of the docs. An example from here is shown below.

Done