Update preset regex and simplify Readme test

Removed the unnecessary YML content manipulation from the Readme test in ReadmeTest.php. Furthermore, updated the regex pattern for alias in presets in the README.md file to case insensitive, easing the matching process. Improved the readability of the description for the preset_database.yml.

README.md

@@ -938,7 +938,7 @@ In fact, this can be considered as partial inheritance.
  - Schemas with presets validate themselves and if there are any obvious issues, you will see them when you try to use
   the schema.
  - Alias in presets must match the regex pattern
-   <!-- auto-update:preset-regex -->`^[a-z0-9_-]+$`<!-- auto-update:/preset-regex -->.
+   <!-- auto-update:preset-regex -->`/^[a-z0-9-_]+$/i`<!-- auto-update:/preset-regex -->.
 
 
 Let's take a look at what this looks like in code.
@@ -953,7 +953,7 @@ of CSV files and rules. It will be much easier to achieve consistency. Very ofte
 [preset_database.yml](schema-examples/preset_database.yml)
 <!-- auto-update:preset-database-yml -->
 ```yml
-name: Common presets for common database columns
+name: Presets for database columns
 description: This schema contains basic rules for database user data.
 
 columns:

tests/ReadmeTest.php

@@ -195,13 +195,7 @@ public function testCheckPresetFeaturesExampleInReadme(): void
 
     public function testCheckPresetRegexInReadme(): void
     {
-        $ymlContent = \implode(
-            "\n",
-            \array_slice(\explode("\n", \file_get_contents('./schema-examples/preset_features.yml')), 12),
-        );
-
         $text = SchemaDataPrep::getAliasRegex();
-
         Tools::insertInReadme('preset-regex', "`{$text}`", true);
     }