Add localInspection extension to plugin.xml

initial.plugin.xml

<idea-plugin>
    <id>com.ruben.codespector</id>
    <name>Codespector</name>
    <vendor email="support@yourcompany.com" url="http://www.yourcompany.com">YourCompany</vendor>

    <description><![CDATA[
    Enter short description for your plugin here.<br>
    <em>most HTML tags may be used</em>
    ]]></description>

    <!-- please see https://plugins.jetbrains.com/docs/intellij/plugin-compatibility.html
         on how to target different products -->
    <depends>com.intellij.modules.platform</depends>
    <depends>org.jetbrains.kotlin</depends>

    <extensions defaultExtensionNs="com.intellij">

        <localInspection
                language="kotlin"
                groupPath="Kotlin"
                groupBundle="messages.InspectionsBundle"
                groupKey="group.names.probable.bugs"
                enabledByDefault="true"
                implementationClass="com.ruben.codespector.SerializedNameInspector"
                displayName="Add 'SerializedName' annotation"
                shortName="SerializedNameInspector"
                runForWholeFile="true" />

    </extensions>

    <actions>
        <!-- Add your actions here -->
    </actions>
</idea-plugin>