Update polyfill comments to reflect secret support.

Author: Pimm

src/communication/NetworkClient.ts

@@ -16,7 +16,8 @@ import breakUrl from './breakUrl';
 import buildUrl, { type SearchParameters } from './buildUrl';
 import dromedaryCase from './dromedaryCase';
 import { idempotencyHeaderName, ResponseWithIdempotencyKey, retryingFetch } from './makeRetrying';
-import { URL } from 'url'; // This isn't necessary for newer node versions, but it allows us to secretly support node 8. Should we ever drop that completely and move to 10+, we can remove this import.
+// The following line is only necessary for Node.js < 10.0.0, which we only secretly support. Should we ever drop that support completely, we can remove this import.
+import { URL } from 'url';
 
 /**
  * Like `[].map` but with support for non-array inputs, in which case this function behaves as if an array was passed

src/communication/breakUrl.ts

@@ -1,4 +1,4 @@
-// If support for Node.js < 10.0.0 is ever dropped, this import can be removed.
+// The following line is only necessary for Node.js < 10.0.0, which we only secretly support. Should we ever drop that support completely, we can remove this import.
 import { URL } from 'url';
 
 import buildFromEntries from '../plumbing/buildFromEntries';

src/communication/buildUrl.ts

@@ -1,4 +1,4 @@
-// If support for Node.js < 10.0.0 is ever dropped, this import can be removed.
+// The following line is only necessary for Node.js < 10.0.0, which we only secretly support. Should we ever drop that support completely, we can remove this import.
 import { URLSearchParams } from 'url';
 
 import { apply, runIf } from 'ruply';

src/plumbing/buildFromEntries.ts

@@ -1,7 +1,8 @@
 /**
  * Returns an object generated from the passed a list of key-value pairs.
  *
- * If support for Node.js < 12.0.0 is ever dropped, this function can be removed in favour of `Object.fromEntries`.
+ * This function only exists to support Node.js < 12.0.0, which we only secretly support. Should we ever drop that
+ * support completely, this function can be removed in favour of `Object.fromEntries`.
  */
 export default ((): (<T>(input: Iterable<readonly [string, T]>) => Record<string, T>) => {
   if (Object.fromEntries != undefined) {

src/plumbing/iteration/HelpfulIterator.ts

@@ -66,9 +66,6 @@ export default class HelpfulIterator<T> implements AsyncIterator<T, void, never>
     this.next = wrappee.next.bind(wrappee);
   }
 
-  // Node.js < 10.0.0 does not support Symbol.asyncIterator. Symbol.asyncIterator therefore resolves to undefined,
-  // which actually creates a method called "undefined" callable as iterator.undefined(). Albeit odd, I don't feel this
-  // warrants a "fix", especially as it only affects old Node.js versions.
   [Symbol.asyncIterator]() {
     return this;
   }