Use Squizlabs Commenting sniffs for Method PHPDoc

This commit addss support for the standard Commenting sniffs relating
to methods only.

Some of the specific sniffs have been disabled, or their severity/type
changed to suit our rules.

Fixes moodlehq#30

Author: andrewnicols

moodle/ruleset.xml

@@ -65,6 +65,58 @@
         </properties>
     </rule>
 
+    <!-- Check phpdoc comments for functions -->
+    <rule ref="Squiz.Commenting.FunctionComment"/>
+
+    <!-- We do not enforce specific formatting of @params with regards spacing -->
+    <rule ref="Squiz.Commenting.FunctionComment.SpacingAfterParamType">
+      <severity>0</severity>
+    </rule>
+    <rule ref="Squiz.Commenting.FunctionComment.SpacingAfterParamName">
+      <severity>0</severity>
+    </rule>
+    <rule ref="Squiz.Commenting.FunctionComment.ParamCommentAlignment">
+      <severity>0</severity>
+    </rule>
+    <rule ref="Squiz.Commenting.FunctionComment.ParamCommentAlignmentExceeded">
+      <severity>0</severity>
+    </rule>
+
+    <!-- Parameter comments are optional, but recommended -->
+    <rule ref="Squiz.Commenting.FunctionComment.MissingParamComment">
+      <type>warning</type>
+      <severity>2</severity>
+    </rule>
+
+    <!-- Parameter comments do not need to start with a capital letter -->
+    <rule ref="Squiz.Commenting.FunctionComment.ParamCommentNotCapital">
+      <severity>0</severity>
+    </rule>
+
+    <!-- Parameter comments do not need to end with a full stop -->
+    <rule ref="Squiz.Commenting.FunctionComment.ParamCommentFullStop">
+      <severity>0</severity>
+    </rule>
+
+    <!-- Type hints are optional, but strongly recommended -->
+    <rule ref="Squiz.Commenting.FunctionComment.TypeHintMissing">
+      <type>warning</type>
+    </rule>
+    <rule ref="Squiz.Commenting.FunctionComment.ScalarTypeHintMissing">
+      <type>warning</type>
+    </rule>
+
+    <!--
+      Sadly this rule does not let you configure it to ignore missing returns if no return is present.
+      We do not recommend use of `@return void` but they mandate it.
+    -->
+    <rule ref="Squiz.Commenting.FunctionComment.MissingReturn">
+      <severity>0</severity>
+    </rule>
+
+
+    <rule ref="Squiz.Commenting.FunctionCommentThrowTag"/>
+
     <rule ref="Squiz.Scope.MethodScope"/>
     <rule ref="Squiz.Scope.StaticThisUsage"/>