docs: Minor fix in the Building Your Project with Gradle guide

    buildTypes { ... }

    productFlavors {

        demo {

            packageName "com.buildsystemexample.app.demo"

            applicationId "com.buildsystemexample.app.demo"

            versionName "1.0-demo"

        }

        full {

            packageName "com.buildsystemexample.app.full"

            applicationId "com.buildsystemexample.app.full"

            versionName "1.0-full"

        }

    }

<p>The product flavor definitions support the same properties as the <code>defaultConfig</code>

element. The base configuration for all flavors is specified in <code>defaultConfig</code>, and each

flavor can override any value. The build file above assigns a different package name to each flavor:

since each flavor definition creates a different app, they each need a distinct package name.</p>

flavor can override any value. The build file above uses the <code>applicationId</code> property

to assign a different package name to each flavor: since each flavor definition creates a

different app, they each need a distinct package name.</p>

<p class="note"><strong>Note:</strong> To distribute your app using

<a href="{@docRoot}google/play/publishing/multiple-apks.html">Multiple APK Support</a> in