Clean edit pass on attributes

[BillWagner]

Fixes #42850: Add a new page to reference attributes that cause the compiler to emit different IL modifiers instead of putting the attribute in the emitted IL.
Fixes #43109: Most of these have been added to the general page. A few are expressed in source differently, and were added to the new pseudo-attributes page.
Fixes #43110: Add a list of attributes that are written by the compiler that shouldn't be added in users' source code.

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Internal previews

📄 File	🔗 Preview link
docs/csharp/language-reference/attributes/general.md	Miscellaneous attributes interpreted by the C# compiler
docs/csharp/language-reference/attributes/pseudo-attributes.md	"Attributes interpreted by the compiler: Pseudo-attributes"
docs/csharp/language-reference/toc.yml	docs/csharp/language-reference/toc
docs/csharp/misc/cs0612.md	Compiler warning (level 1) CS0612
docs/csharp/misc/cs0619.md	"Compiler Error CS0619"
docs/csharp/specification/toc.yml	docs/csharp/specification/toc
docs/csharp/versioning.md	Versioning in C#
docs/csharp/whats-new/csharp-12.md	What's new in C# 12
docs/fundamentals/networking/http/httpclient-guidelines.md	Guidelines for using HttpClient
docs/fundamentals/runtime-libraries/preview-apis.md	docs/fundamentals/runtime-libraries/preview-apis

[jnm2]

Though, creating custom attributes with the same name in a different namespace is okay, and custom attributes don't go in the System namespace.

[jnm2]

[UnmanagedCallersOnly] is actually something the user must apply in code in order to use the unmanaged calling convention specifically with the delegate* feature:

using System.Runtime.InteropServices;

unsafe
{
    delegate* unmanaged<void> someFuncPointer = &SomeMethod;
}

[UnmanagedCallersOnly] // Compilation fails if this is removed
static void SomeMethod() { }

[jnm2]

This one could have a note parallel to the note added for InAttribute, saying "Use the out modifier."