docs: Improve flat config ignores docs (#17997)

* docs: Improve flat config ignores docs

fixes #17822

* Fix links

docs/src/use/configure/ignore.md

@@ -38,7 +38,31 @@ You can also ignore files on the command line using `--ignore-pattern`, such as:
 npx eslint . --ignore-pattern ".config/*"
 ```
 
-## Unignoring Files
+## Ignoring Directories
+
+Ignoring directories works the same way as ignoring files, by placing a pattern in the `ignores` key of a configuration object with no other keys. For example, the following ignores the `.config` directory as a whole (meaning file search will not traverse into it at all):
+
+```js
+// eslint.config.js
+export default [
+    {
+        ignores: [".config/"]
+    }
+];
+```
+
+Unlike `.gitignore`, an ignore pattern like `.config` will only ignore the `.config` directory in the same directory as the configuration file. If you want to recursively ignore all directories named `.config`, you need to use `**/.config/`, as in this example:
+
+```js
+// eslint.config.js
+export default [
+    {
+        ignores: ["**/.config/"]
+    }
+];
+```
+
+## Unignoring Files and Directories
 
 You can also unignore files and directories that are ignored by previous patterns, including the default patterns. For example, this config unignores `node_modules/mylibrary`:
 

docs/src/use/configure/index.md

@@ -52,5 +52,6 @@ All of these options give you fine-grained control over how ESLint treats your c
 [**Ignore Files**](ignore)
 
 * [Ignoring Files](./ignore#ignoring-files)
-* [Unignoring Files](./ignore#unignoring-files)
+* [Ignoring Directories](./ignore#ignoring-directories)
+* [Unignoring Files and Directories](./ignore#unignoring-files-and-directories)
 * [Ignored File Warnings](./ignore#ignored-file-warnings)

docs/src/use/configure/migration-guide.md

@@ -524,7 +524,7 @@ config/*
 # ...other ignored files
 ```
 
-`ignorePatterns` example:
+Here are the same patterns represented as `ignorePatterns` in a `.eslintrc.js` file:
 
 ```javascript
 // .eslintrc.js
@@ -534,7 +534,7 @@ module.exports = {
 };
 ```
 
-Here are the same files ignore patterns in flat config:
+The equivalent ignore patterns in flat config look like this:
 
 ```javascript
 export default [
@@ -545,7 +545,11 @@ export default [
 ];
 ```
 
-Also, with flat config, dotfiles (e.g. `.dotfile.js`) are no longer ignored by default. If you want to ignore dotfiles, add files ignore pattern `"**/.*"`.
+In `.eslintignore`, `temp.js` ignores all files named `temp.js`, whereas in flat config, you need to specify this as `**/temp.js`. The pattern `temp.js` in flat config only ignores a file named `temp.js` in the same directory as the configuration file.
+
+::: important
+In flat config , dotfiles (e.g. `.dotfile.js`) are no longer ignored by default. If you want to ignore dotfiles, add an ignore pattern of `"**/.*"`.
+:::
 
 ### Linter Options