Don't expose HtmlTriggerCharacters set

Rather than directly exposing a set, this change adds instance methods to test for valid HTML triggers.

src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/CompletionTriggerAndCommitCharacters.cs

@@ -25,7 +25,8 @@ internal class CompletionTriggerAndCommitCharacters(LanguageServerFeatureOptions
     private static readonly FrozenSet<string> s_razorTriggerCharacters = new[] { RazorDelegationTriggerCharacter, "<", ":", " " }.ToFrozenSet();
     private static readonly FrozenSet<string> s_razorDelegationTriggerCharacters = new[] { RazorDelegationTriggerCharacter }.ToFrozenSet();
     private static readonly FrozenSet<string> s_csharpTriggerCharacters = new[] { " ", "(", "=", "#", ".", "<", "[", "{", "\"", "/", ":", "~" }.ToFrozenSet();
-    public FrozenSet<string> HtmlTriggerCharacters =>
+
+    private FrozenSet<string> HtmlTriggerCharacters =>
         _languageServerFeatureOptions.UseVsCodeCompletionTriggerCharacters ? s_vsCodeHtmlTriggerCharacters : s_vsHtmlTriggerCharacters;
 
     private FrozenSet<string> AllDelegationTriggerCharacters => _allDelegationTriggerCharacters
@@ -52,6 +53,9 @@ public bool IsValidCSharpTrigger(CompletionContext completionContext)
     public bool IsValidDelegationTrigger(CompletionContext completionContext)
         => IsValidTrigger(AllDelegationTriggerCharacters, completionContext);
 
+    public bool IsValidHtmlTrigger(CompletionContext completionContext)
+        => IsValidTrigger(HtmlTriggerCharacters, completionContext);
+
     public bool IsValidRazorTrigger(CompletionContext completionContext)
         => IsValidTrigger(s_razorTriggerCharacters, completionContext);
 
@@ -61,6 +65,9 @@ public bool IsCSharpTriggerCharacter(string ch)
     public bool IsDelegationTriggerCharacter(string ch)
         => AllDelegationTriggerCharacters.Contains(ch);
 
+    public bool IsHtmlTriggerCharacter(string ch)
+        => HtmlTriggerCharacters.Contains(ch);
+
     public bool IsRazorTriggerCharacter(string ch)
         => s_razorTriggerCharacters.Contains(ch);
 

src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/Delegation/DelegatedCompletionHelper.cs

@@ -69,7 +69,7 @@ internal static class DelegatedCompletionHelper
             // For HTML we don't want to delegate to HTML language server is completion is due to a trigger characters that is not
             // HTML trigger character. Doing so causes bad side effects in VSCode HTML client as we will end up with non-matching
             // completion entries
-            return triggerAndCommitCharacters.HtmlTriggerCharacters.Contains(triggerCharacter) ? context : null;
+            return triggerAndCommitCharacters.IsHtmlTriggerCharacter(triggerCharacter) ? context : null;
         }
 
         // Trigger character not associated with the current language. Transform the context into an invoked context.

src/Razor/src/Microsoft.VisualStudio.LanguageServices.Razor/LanguageClient/Cohost/CohostDocumentCompletionEndpoint.cs

@@ -137,14 +137,15 @@ public ImmutableArray<Registration> GetRegistrations(VSInternalClientCapabilitie
             CommitElementsWithSpace: clientSettings.AdvancedSettings.CommitElementsWithSpace);
         using var _ = HashSetPool<string>.GetPooledObject(out var existingHtmlCompletions);
 
-        if (CompletionTriggerAndCommitCharacters.IsValidTrigger(_triggerAndCommitCharacters.HtmlTriggerCharacters, completionContext))
+        if (_triggerAndCommitCharacters.IsValidHtmlTrigger(completionContext))
         {
             // We can just blindly call HTML LSP because if we are in C#, generated HTML seen by HTML LSP may return
             // results we don't want to show. So we want to call HTML LSP only if we know we are in HTML content.
             if (documentPositionInfo.LanguageKind == RazorLanguageKind.Html)
             {
-                htmlCompletionList = await GetHtmlCompletionListAsync(request, razorDocument, razorCompletionOptions, cancellationToken)
-                                                                      .ConfigureAwait(false);
+                htmlCompletionList = await GetHtmlCompletionListAsync(
+                    request, razorDocument, razorCompletionOptions, cancellationToken).ConfigureAwait(false);
+
                 if (htmlCompletionList is not null)
                 {
                     existingHtmlCompletions.UnionWith(htmlCompletionList.Items.Select(i => i.Label));