Missing mapping with ToDocs command

When I worked on https://github.com/dotnet/dotnet-api-docs/pull/7129 the DocsPortingTool didn't map some methods to xml files. I had to do it manually.

- `M:System.Net.Http.HttpRequestOptions.TryGetValue``1(System.Net.Http.HttpRequestOptionsKey{``0},``0@)`
- `M:System.Net.Http.HttpRequestOptions.Set``1(System.Net.Http.HttpRequestOptionsKey{``0},``0)`

The command I used was `DocsPortingTool -Direction ToDocs -Docs c:\Dev\dotnet-api-docs\xml -IntelliSense C:\dev\runtime\artifacts\bin\System.Net.Http\ -IncludedAssemblies System.Net.Http -IncludedNamespaces System.Net.Http -Save true` on this code https://github.com/dotnet/runtime/pull/58896/files

首先，复现与 System.Net.Http 程序集以及列出的 XML 和 IntelliSense 路径一起显示的 DocsPortingTool 命令。使用所引用的 runtime pull request 中的源签名，调查 ToDocs 命令如何映射两个通用的 HttpRequestOptions 方法。完成的标准是两个方法都能自动映射到其 XML 文档文件。

由索引模型根据 Issue 内容生成。