Corrected description of ExpressionVisitor.VisitAndConvert

[svick]

The original description of this overload was worded as if the collection operated on a single expression. But it operates on a collection of expressions, so I have updated the documentation to reflect that.

I have also noticed that many methods in this file have <remarks>To be added.</remarks>. Are they useful to track missing documentation, or should they just be removed?

[rpetrusha]

Thanks for fixing noticing and fixing this longstanding issue, @svick. These changes look good.

In terms of <remarks>To be added.</remarks>, the boilerplate was evidently added when a remarks tag was present in documents in our old authoring system but there was no content. The build appears to ignore "To be added" remarks, and a search shows that <remarks> with "To be added." as the content appears in 12,280 additional topics. So I don't think that there's anything to be gained by asking you to remove them from this file.

So I'll approve and close your PR. Again, thanks for submitting it.