Merge pull request #528 from kenjis/fix-docs-concepts.md

docs: fix property notation

Author: kenjis

docs/concepts.md

@@ -25,7 +25,7 @@ on the standard Config class if nothing is found in the database.
 ## User Providers
 
 You can use your own models to handle user persistence. Shield calls this the "User Provider" class. A default model
-is provided for you at `CodeIgniter\Shield\Models\UserModel`. You can change this in the `Config\Auth->userProvider` setting.
+is provided for you at `CodeIgniter\Shield\Models\UserModel`. You can change this in the `Config\Auth::$userProvider` setting.
 The only requirement is that your new class MUST extend the provided `UserModel`.
 
 ```php
@@ -57,13 +57,13 @@ systems that are appropriate for your application. The following Validators are
     like ensuring it contained a symbol, a number, etc. According to the current
     [NIST recommendations](https://pages.nist.gov/800-63-3/sp800-63b.html) this only enforces a
     minimum length on the password. You can define the minimum length in
-    `Config\Auth->public $minimumPasswordLength;` This is enabled by default. The default minimum
+    `Config\Auth::$minimumPasswordLength` This is enabled by default. The default minimum
     value is `8`.
 - **NothingPersonalValidator** will compare the password against any fields that have been specified
-    in `Config\Auth->personalFields`, like first or last names, etc. Additionally, it compares it
+    in `Config\Auth::$personalFields`, like first or last names, etc. Additionally, it compares it
     against a few simple variations of the username. If the given password too closely matches
     any of the personal information, it will be rejected. The similarity value is defined in
-     `Config\Auth->maxSimilarity`. The default value is 50, but see the docblock in the config
+     `Config\Auth::$maxSimilarity`. The default value is 50, but see the docblock in the config
      file for more details. This is enabled by default.
 - **DictionaryValidator** will compare the password against a provided file with about 600,000
     frequently used passwords that have been seen in various data dumps over the years. If the
@@ -76,7 +76,7 @@ systems that are appropriate for your application. The following Validators are
     find acceptable. You should use either this validator or the `DictionaryValidator`, not both.
     This is disabled by default.
 
-You can choose which validators are used in `Config\Auth->passwordValidators`:
+You can choose which validators are used in `Config\Auth::$passwordValidators`:
 
 ```php
 public $passwordValidators = [