Remove interactive snippets

[BillWagner]

This PR removes interactive snippets from every namespace except System.

Contributes to dotnet/docs#50331

Notes for reviewers:

1. The diff looks a bit weird because the diff algorithm doesn't prefer words, so the i from "interactive" is outside of the diff, and the diff shows I removed the i from the following id= node.
2. I looked at several of the XML files, and I didn't find any remarks about using the interactive capability. Nor did I find other instances of include files with explanations.

[Copilot]

Pull request overview

This PR removes the interactive="try-dotnet" attribute from code snippet references across multiple namespaces in XML documentation files, excluding the System namespace. The changes are part of an effort to discontinue interactive snippet functionality in the documentation.

Key Changes:

• Systematic removal of interactive="try-dotnet" attributes from :::code elements
• Affects documentation in System.Web, System.Text, System.Text.RegularExpressions, System.Security.Cryptography, System.Reflection, System.Numerics, System.Globalization, System.Collections.Specialized, and System.Collections.Generic namespaces
• All other attributes (language, source, id) are preserved

Reviewed changes

Copilot reviewed 79 out of 79 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
xml/System.Web/HttpUtility.xml	Removed interactive attribute from 1 code snippet
xml/System.Text/UnicodeEncoding.xml	Removed interactive attribute from 7 code snippets
xml/System.Text/UTF8Encoding.xml	Removed interactive attribute from 18 code snippets
xml/System.Text/UTF7Encoding.xml	Removed interactive attribute from 1 code snippet
xml/System.Text/UTF32Encoding.xml	Removed interactive attribute from 2 code snippets
xml/System.Text/StringBuilder.xml	Removed interactive attribute from 18 code snippets
xml/System.Text/Encoding.xml	Removed interactive attribute from 26 code snippets
xml/System.Text/Encoder.xml	Removed interactive attribute from 1 code snippet
xml/System.Text/Decoder.xml	Removed interactive attribute from 1 code snippet
xml/System.Text/ASCIIEncoding.xml	Removed interactive attribute from 3 code snippets
xml/System.Text.RegularExpressions/*.xml	Removed interactive attribute from multiple code snippets across Regex-related files
xml/System.Security.Cryptography/*.xml	Removed interactive attribute from multiple code snippets across cryptography-related files
xml/System.Reflection/PropertyInfo.xml	Removed interactive attribute from 1 code snippet
xml/System.Numerics/*.xml	Removed interactive attribute from multiple code snippets in Complex and BigInteger files
xml/System.Globalization/*.xml	Removed interactive attribute from multiple code snippets across globalization files
xml/System.Collections.Specialized/*.xml	Removed interactive attribute from multiple code snippets across specialized collections
xml/System.Collections.Generic/*.xml	Removed interactive attribute from multiple code snippets across generic collections

The changes are consistent and systematic throughout all files. No issues were identified in the review.