doc: clarify fallback behavior of module require

PR-URL: https://github.com/nodejs/node/pull/22494
Fixes: https://github.com/nodejs/node/issues/22464
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: George Adams <george.adams@uk.ibm.com>

doc/api/modules.md

@@ -352,15 +352,8 @@ If this was in a folder at `./some-library`, then
 
 This is the extent of Node.js's awareness of `package.json` files.
 
-If the file specified by the `'main'` entry of `package.json` is missing and
-can not be resolved, Node.js will report the entire module as missing with the
-default error:
-
-```txt
-Error: Cannot find module 'some-library'
-```
-
-If there is no `package.json` file present in the directory, then Node.js
+If there is no `package.json` file present in the directory, or if the
+`'main'` entry is missing or cannot be resolved, then Node.js
 will attempt to load an `index.js` or `index.node` file out of that
 directory. For example, if there was no `package.json` file in the above
 example, then `require('./some-library')` would attempt to load:
@@ -368,6 +361,13 @@ example, then `require('./some-library')` would attempt to load:
 * `./some-library/index.js`
 * `./some-library/index.node`
 
+If these attempts fail, then Node.js will report the entire module as missing
+with the default error:
+
+```txt
+Error: Cannot find module 'some-library'
+```
+
 ## Loading from `node_modules` Folders
 
 <!--type=misc-->