Clarify SymbolDisplayDelegateStyle documentation to reference SymbolDisplayParameterOptions

[Copilot]

Fixes #11232

Problem

The documentation for SymbolDisplayDelegateStyle.NameAndSignature was misleading. The example showed "void SomeDelegate(int x)", which suggested that parameter names would always be displayed when using this option. However, the actual behavior depends on the SymbolDisplayParameterOptions flags being set.

Users were confused when NameAndSignature didn't show parameter names or details, not realizing they needed to also specify appropriate SymbolDisplayParameterOptions flags to control what appears within the signature.

Changes

Updated the documentation for both NameAndParameters and NameAndSignature to:

1. Clarify the separation of concerns:

   • SymbolDisplayDelegateStyle controls whether the signature part appears
   • SymbolDisplayParameterOptions controls what appears in the signature (types, names, modifiers, etc.)

2. Add explicit references:

   • Changed vague wording like "will be determined by the other flags passed" to explicitly reference <see cref="SymbolDisplayParameterOptions"/>

3. Fix misleading examples:

   • Changed examples from "void SomeDelegate(int x)" to "void SomeDelegate(int, int)" to avoid implying parameter names are automatically included
   • Parameter names only appear when SymbolDisplayParameterOptions.IncludeName is set

Example

var format1 = new SymbolDisplayFormat(
    delegateStyle: SymbolDisplayDelegateStyle.NameAndSignature,
    parameterOptions: SymbolDisplayParameterOptions.IncludeType);
// Output: "void SomeDelegate(int, bool)" - types only, no parameter names

var format2 = new SymbolDisplayFormat(
    delegateStyle: SymbolDisplayDelegateStyle.NameAndSignature,
    parameterOptions: SymbolDisplayParameterOptions.IncludeType | SymbolDisplayParameterOptions.IncludeName);
// Output: "void SomeDelegate(int a, bool b)" - types AND names

The updated documentation makes it clear that users need to set the appropriate SymbolDisplayParameterOptions flags to get the desired level of detail in the signature.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>INamedType.ToDisplayString omits delegate's parameters</issue_title>
<issue_description>Version Used: 4.3.0

Steps to Reproduce:

SymbolDisplayFormat options:

var format = new SymbolDisplayFormat(
        globalNamespaceStyle: SymbolDisplayGlobalNamespaceStyle.Omitted,
        typeQualificationStyle: SymbolDisplayTypeQualificationStyle.NameAndContainingTypesAndNamespaces,
        delegateStyle: SymbolDisplayDelegateStyle.NameAndSignature,
        miscellaneousOptions: SymbolDisplayMiscellaneousOptions.UseSpecialTypes);

Code example:

namespace A
{
    public delegate bool SyntaxReceiverCreator(int a, bool b);
}

Expected Behavior:
as delegateStyle: SymbolDisplayDelegateStyle.NameAndSignature is active, I expect INamedType.ToDisplayString(format) produces output:

bool SyntaxReceiverCreator(int a, bool b)

Actual Behavior:
INamedType.ToDisplayString(format) produces output (without parameters):

bool A.SyntaxReceiverCreator()

From parameter description:

SymbolDisplayDelegateStyle.NameAndSignature - Shows the name and the signature of the delegate (e.g. "void SomeDelegate(int x)").

Issue in arcade: dotnet/arcade#11232</issue_description>

<agent_instructions>Copilot, can you clarify teh docs for NameAndSignature. It should mention that this flag is just to determine if the signature will be there or not (the (...) part), but not what is shown in the signature. Control of what is in the signature should be explicitly stated using the right SymbolDisplayParameterOptions flags. </agent_instructions>

Comments on the Issue (you are @copilot in this section)

@RikkiGibson The `A.` prefix is expected since we are using `SymbolDisplayTypeQualificationStyle.NameAndContainingTypesAndNamespaces`.

I agree that the documentation of SymbolDisplayDelegateStyle.NameAndSignature indicates that the parameters are expected to be displayed. Let's fix that.</comment_new>
<comment_new>@CyrusNajmabadi
@RikkiGibson i'm thinking this is by-design. The parameter controls if we want the signature or not. But then the format of the signature is controlled by SymbolDisplayParameterOptions. So i think what we want instead is to just doc NameAndSignature to indicate that Parameter options should be provided.</comment_new>

• Fixes INamedType.ToDisplayString omits delegate's parameters #64632

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[CyrusNajmabadi]

@dotnet/roslyn-compiler doc only change.

[CyrusNajmabadi]

Closing in favor of #80885