Added paragraph on creating DataFrame from list of namedtuples
- [x] closes #35438 

Is a whatsnew entry necessary for this PR?
> Is a whatsnew entry necessary for this PR?

no @arw2019 Thanks for the suggestions, I've updated the text and one of the examples.

I'm confused about the indentation though, I've checked that it consists of 4 spaces, and throughout the file it's a mix of 3- and 4-space indentation actually... thanks @sjvrijn 