fix: set the correct fallback for Snippet completion (#148)

Co-authored-by: ayame113 <ayame113@users.noreply.github.com>

Author: ayame113

lib/adapters/autocomplete-adapter.ts

@@ -492,7 +492,7 @@ export default class AutocompleteAdapter {
    */
   public static applySnippetToSuggestion(item: CompletionItem, suggestion: SnippetSuggestion): void {
     if (item.insertTextFormat === InsertTextFormat.Snippet) {
-      suggestion.snippet = item.textEdit != null ? item.textEdit.newText : item.insertText || ""
+      suggestion.snippet = item.textEdit != null ? item.textEdit.newText : item.insertText || item.label
     }
   }
 

test/adapters/autocomplete-adapter.test.ts

@@ -248,6 +248,11 @@ describe("AutoCompleteAdapter", () => {
           value: "documentation",
         },
       },
+      {
+        label: "sorawo",
+        sortText: "f",
+        insertTextFormat: ls.InsertTextFormat.Snippet,
+      },
     ]
 
     beforeEach(() => {
@@ -284,6 +289,9 @@ describe("AutoCompleteAdapter", () => {
       expect(results[4].description).is.undefined
       expect(results[4].descriptionMarkdown).equals("documentation")
       expect(results[4].rightLabel).equals("details")
+
+      expect(results[5].displayText).equals("sorawo")
+      expect((results[5] as SnippetSuggestion).snippet).equals("sorawo")
     })
 
     it("respects onDidConvertCompletionItem", async () => {