Add documentation regarding 'pluginVersion' string (#39)

build.gradle.kts

@@ -100,7 +100,7 @@ tasks {
                     val end = "<!-- Plugin description end -->"
 
                     if (!containsAll(listOf(start, end))) {
-                        throw GradleException("Plugin description section not found in README.md file:\n$start ... $end")
+                        throw GradleException("Plugin description section not found in README.md:\n$start ... $end")
                     }
                     subList(indexOf(start) + 1, indexOf(end))
                 }.joinToString("\n").run { markdownToHTML(this) }
@@ -118,6 +118,9 @@ tasks {
     publishPlugin {
         dependsOn("patchChangelog")
         token(System.getenv("PUBLISH_TOKEN"))
+        // pluginVersion is based on the SemVer (https://semver.org) and supports pre-release labels, like 2.1.7-alpha.3
+        // Specify pre-release label to publish the plugin in a custom Release Channel automatically. Read more:
+        // https://jetbrains.org/intellij/sdk/docs/tutorials/build_system/deployment.html#specifying-a-release-channel
         channels(pluginVersion.split('-').getOrElse(1) { "default" }.split('.').first())
     }
 }