Add the phpcs.xml dist file and some small adjustments

Here we are introducing the phpcs.xml.dist file that will
guide our coding style within moodle-cs.

- It scans all the code but vendor and fixtures directories.
- It's the complete PSR12 standard but allowing multi line function
  declarations to have the opening curly bracket in the same line.
- With line length adjusted to 132 / 180.
- And a few more sniffs, not part of the PSR12, but good for
  readability (hopefully non-controversial):
  - && and || logical operators.
  - Short array syntax.
  - Space after commas.
  - Comma at the end of multi-line arrays.
  - PHPCompatibility standard to check for >=7.4 (with an exception
    about T_ENUM false positives).

And that's it!

Then, apart of the above, small adjustments to the composer.json
and .gitignore files.

.gitignore

@@ -1,10 +1,20 @@
-vendor
+# Composer stuff
 composer.lock
-phpcs.xml
+composer.phar
+
+# PHP_CodeSniffer
 .phpcs.xml
+phpcs.xml
+!phpcs.xml.dist
+
+# PHPUnit
 .phpunit.result.cache
 phpunit.xml
-.phplint-cache
 clover.xml
 .phpunit.cache
+
+# PHPlin
+phplint.cache
+
+# IDEs and editors
 .vscode

composer.json

@@ -22,6 +22,8 @@
         }
     ],
     "require": {
+        "php": ">=7.4.0",
+        "ext-json": "*",
         "dealerdirect/phpcodesniffer-composer-installer": "^1.0.0",
         "squizlabs/php_codesniffer": "^3.9.0",
         "phpcsstandards/phpcsextra": "^1.2.1",

phpcs.xml.dist

@@ -0,0 +1,46 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ruleset>
+    <description>The coding rules configuration for the moodle-cs project.</description>
+
+    <!-- We don't want to analyse these -->
+    <exclude-pattern>*/vendor/*</exclude-pattern>
+    <exclude-pattern>*/Tests/fixtures/*</exclude-pattern>
+    <exclude-pattern>*/Tests/*/fixtures/*</exclude-pattern>
+
+    <!-- PSR12 with a few exceptions and adjustments -->
+    <rule ref="PSR12">
+        <exclude name="Squiz.Functions.MultiLineFunctionDeclaration.BraceOnSameLine"/>
+    </rule>
+
+    <!-- Some more chars don't hurt too much -->
+    <rule ref="Generic.Files.LineLength">
+        <properties>
+            <property name="lineLimit" value="132"/>
+            <property name="absoluteLineLimit" value="180"/>
+        </properties>
+    </rule>
+
+    <!-- We want to enforce && and || instead of and and or -->
+    <rule ref="Squiz.Operators.ValidLogicalOperators"/>
+
+    <!-- We want to use always the short array syntax -->
+    <rule ref="Generic.Arrays.DisallowLongArraySyntax"/>
+
+    <!-- We went better commas managing -->
+    <!-- Space after comma -->
+    <rule ref="moodle.WhiteSpace.SpaceAfterComma"/>
+    <!-- Comma at the end of multi-line arrays -->
+    <rule ref="NormalizedArrays.Arrays.CommaAfterLast">
+        <exclude name="NormalizedArrays.Arrays.CommaAfterLast.MissingMultiLineCloserSameLine" />
+    </rule>
+
+    <!--PHPCompetibility configuration-->
+    <rule ref="./vendor/phpcompatibility/php-compatibility/PHPCompatibility/ruleset.xml"/>
+    <config name="testVersion" value="7.4-"/>
+
+    <!-- These are false positives because CodeSniffer creates them when needed.
+        TODO: Delete this once we raise minimum requirements to PHP 8.0. -->
+    <rule ref="PHPCompatibility.Constants.NewConstants">
+        <exclude name="PHPCompatibility.Constants.NewConstants.newConstants.t_enumFound"/>
+    </rule>
+</ruleset>