fix(debugging): stop debugger displays rendering as a bare null (#2315)

- Give every debugger display literal text alongside its placeholder. A
  display made of nothing but one member rendered as a bare `null` the
  moment that member was null, which reads as though the object itself
  does not exist.
- ApiResponse<T> was the reported case: hovering a response that came back
  without content showed `null`, sending the reader looking for a
  NullReferenceException that was never thrown. It now leads with the type
  and the status code.
- Ten other shipped types carried the same shape and are fixed with it.
- Add DebuggerDisplayTests, which walks the shipped assemblies and fails
  any display whose sole placeholder can be null, plus any placeholder
  naming a member that does not exist.

Closes #2313

Author: glennawatson

src/Refit.HttpClientFactory/PublicAPI/net10.0/PublicAPI.txt

@@ -121,7 +121,7 @@ public interface ISettingsFor
 {
     Refit.RefitSettings? Settings { get; }
 }
-[System.Diagnostics.DebuggerDisplay("{Settings}")]
+[System.Diagnostics.DebuggerDisplay("SettingsFor: {Settings}")]
 public class SettingsFor<T> : Refit.ISettingsFor
 {
     public SettingsFor(Refit.RefitSettings? settings) { }

src/Refit.HttpClientFactory/PublicAPI/net11.0/PublicAPI.txt

@@ -121,7 +121,7 @@ public interface ISettingsFor
 {
     Refit.RefitSettings? Settings { get; }
 }
-[System.Diagnostics.DebuggerDisplay("{Settings}")]
+[System.Diagnostics.DebuggerDisplay("SettingsFor: {Settings}")]
 public class SettingsFor<T> : Refit.ISettingsFor
 {
     public SettingsFor(Refit.RefitSettings? settings) { }

src/Refit.HttpClientFactory/PublicAPI/net462/PublicAPI.txt

@@ -57,7 +57,7 @@ public interface ISettingsFor
 {
     Refit.RefitSettings? Settings { get; }
 }
-[System.Diagnostics.DebuggerDisplay("{Settings}")]
+[System.Diagnostics.DebuggerDisplay("SettingsFor: {Settings}")]
 public class SettingsFor<T> : Refit.ISettingsFor
 {
     public SettingsFor(Refit.RefitSettings? settings) { }

src/Refit.HttpClientFactory/PublicAPI/net470/PublicAPI.txt

@@ -57,7 +57,7 @@ public interface ISettingsFor
 {
     Refit.RefitSettings? Settings { get; }
 }
-[System.Diagnostics.DebuggerDisplay("{Settings}")]
+[System.Diagnostics.DebuggerDisplay("SettingsFor: {Settings}")]
 public class SettingsFor<T> : Refit.ISettingsFor
 {
     public SettingsFor(Refit.RefitSettings? settings) { }

src/Refit.HttpClientFactory/PublicAPI/net471/PublicAPI.txt

@@ -57,7 +57,7 @@ public interface ISettingsFor
 {
     Refit.RefitSettings? Settings { get; }
 }
-[System.Diagnostics.DebuggerDisplay("{Settings}")]
+[System.Diagnostics.DebuggerDisplay("SettingsFor: {Settings}")]
 public class SettingsFor<T> : Refit.ISettingsFor
 {
     public SettingsFor(Refit.RefitSettings? settings) { }

src/Refit.HttpClientFactory/PublicAPI/net472/PublicAPI.txt

@@ -57,7 +57,7 @@ public interface ISettingsFor
 {
     Refit.RefitSettings? Settings { get; }
 }
-[System.Diagnostics.DebuggerDisplay("{Settings}")]
+[System.Diagnostics.DebuggerDisplay("SettingsFor: {Settings}")]
 public class SettingsFor<T> : Refit.ISettingsFor
 {
     public SettingsFor(Refit.RefitSettings? settings) { }

src/Refit.HttpClientFactory/PublicAPI/net48/PublicAPI.txt

@@ -57,7 +57,7 @@ public interface ISettingsFor
 {
     Refit.RefitSettings? Settings { get; }
 }
-[System.Diagnostics.DebuggerDisplay("{Settings}")]
+[System.Diagnostics.DebuggerDisplay("SettingsFor: {Settings}")]
 public class SettingsFor<T> : Refit.ISettingsFor
 {
     public SettingsFor(Refit.RefitSettings? settings) { }

src/Refit.HttpClientFactory/PublicAPI/net481/PublicAPI.txt

@@ -57,7 +57,7 @@ public interface ISettingsFor
 {
     Refit.RefitSettings? Settings { get; }
 }
-[System.Diagnostics.DebuggerDisplay("{Settings}")]
+[System.Diagnostics.DebuggerDisplay("SettingsFor: {Settings}")]
 public class SettingsFor<T> : Refit.ISettingsFor
 {
     public SettingsFor(Refit.RefitSettings? settings) { }

src/Refit.HttpClientFactory/PublicAPI/net8.0/PublicAPI.txt

@@ -105,7 +105,7 @@ public interface ISettingsFor
 {
     Refit.RefitSettings? Settings { get; }
 }
-[System.Diagnostics.DebuggerDisplay("{Settings}")]
+[System.Diagnostics.DebuggerDisplay("SettingsFor: {Settings}")]
 public class SettingsFor<T> : Refit.ISettingsFor
 {
     public SettingsFor(Refit.RefitSettings? settings) { }

src/Refit.HttpClientFactory/PublicAPI/net9.0/PublicAPI.txt

@@ -121,7 +121,7 @@ public interface ISettingsFor
 {
     Refit.RefitSettings? Settings { get; }
 }
-[System.Diagnostics.DebuggerDisplay("{Settings}")]
+[System.Diagnostics.DebuggerDisplay("SettingsFor: {Settings}")]
 public class SettingsFor<T> : Refit.ISettingsFor
 {
     public SettingsFor(Refit.RefitSettings? settings) { }