Address new TypeScript warnings in core files, improve type definitions.

lib/md046.mjs

@@ -3,10 +3,9 @@
 import { addErrorDetailIf } from "../helpers/helpers.cjs";
 import { filterByTypesCached } from "./cache.mjs";
 
-const tokenTypeToStyle = {
-  "codeFenced": "fenced",
-  "codeIndented": "indented"
-};
+/** @typedef {import("markdownlint").MicromarkTokenType} MicromarkTokenType */
+
+const tokenTypeToStyle = (/** @type {MicromarkTokenType} */ tokenType) => (tokenType === "codeFenced") ? "fenced" : "indented";
 
 /** @type {import("markdownlint").Rule} */
 export default {
@@ -19,13 +18,14 @@ export default {
     for (const token of filterByTypesCached([ "codeFenced", "codeIndented" ])) {
       const { startLine, type } = token;
       if (expectedStyle === "consistent") {
-        expectedStyle = tokenTypeToStyle[type];
+        expectedStyle = tokenTypeToStyle(type);
       }
       addErrorDetailIf(
         onError,
         startLine,
         expectedStyle,
-        tokenTypeToStyle[type]);
+        tokenTypeToStyle(type)
+      );
     }
   }
 };