Add string properties declaration to the completion list

src/services/completions.ts

@@ -965,6 +965,9 @@ namespace ts.Completions {
                     symbolToOriginInfoMap[getSymbolId(firstAccessibleSymbol)] =
                         !moduleSymbol || !isExternalModuleSymbol(moduleSymbol) ? { kind: SymbolOriginInfoKind.SymbolMemberNoExport } : { kind: SymbolOriginInfoKind.SymbolMemberExport, moduleSymbol, isDefaultExport: false };
                 }
+                else if (preferences.includeCompletionsWithInsertText) {
+                    symbols.push(symbol);
+                }
             }
             else {
                 symbols.push(symbol);

tests/cases/fourslash/completionForComputedStringProperties.ts

@@ -0,0 +1,18 @@
+/// <reference path="fourslash.ts" />
+
+//// const p2 = "p2";
+//// interface A {
+////     ["p1"]: string;
+////     [p2]: string;
+//// }
+//// declare const a: A;
+//// a[|./**/|]
+
+verify.completions({
+    marker: "",
+    exact: [
+        { name: "p1" },
+        { name: "p2", insertText: '[p2]', replacementSpan: test.ranges()[0] },
+    ],
+    preferences: { includeInsertTextCompletions: true },
+});