Document SRM regex approach/algorithms/terminology in README.md

[stephentoub]

System.Text.RegularExpressions has a README.md file that provides an overview of the library's design. That should be updated, including adding details on the new NonBacktracking implementation and key terminology/algorithms used throughout it.

[ghost]

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Issue Details

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Author:	stephentoub
Assignees:	-
Labels:	area-System.Text.RegularExpressions, untriaged
Milestone:	-

[joperezr]

That README file has now been deleted as it was very out-of-date already given all the changes that went in for 7.0. That said, there are several issues in Regex that are documentation only that are meant to call out these kinds of designs. Do you think we should add an updated README back? or should we document this in the code via comments or perhaps via remarks on the relevant types?

[stephentoub]

Comments in code are fine (preferable, IMHO)

[stephentoub]

I'm going to close this. There are a lot of comments already, and while more would be wonderful and encouraged, it doesn't need to be tracked by an issue anymore nor block 7.0's release.