Fix bigInt completions (microsoft#45059)

* Fix bigInt completions

* Added regresion test

Author: armanio123

src/services/completions.ts

@@ -2013,7 +2013,8 @@ namespace ts.Completions {
             const result = isInStringOrRegularExpressionOrTemplateLiteral(contextToken) ||
                 isSolelyIdentifierDefinitionLocation(contextToken) ||
                 isDotOfNumericLiteral(contextToken) ||
-                isInJsxText(contextToken);
+                isInJsxText(contextToken) ||
+                isBigIntLiteral(contextToken);
             log("getCompletionsAtPosition: isCompletionListBlocker: " + (timestamp() - start));
             return result;
         }

tests/cases/fourslash/completionsBigIntShowNoCompletions.ts

@@ -0,0 +1,9 @@
+/// <reference path="fourslash.ts" />
+
+//// declare const SSL_OP_SSLEAY_080_CLIENT_DH_BUG: number
+//// const foo = 0n/*1*/;
+
+verify.completions({
+  marker: '1',
+  exact: []
+});