plugin_content.md: rework trees using PlantUML, minor edits

topics/basics/plugin_structure/plugin_content.md

@@ -1,18 +1,19 @@
 # Plugin Content
 
-<!-- Copyright 2000-2023 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license. -->
+<!-- Copyright 2000-2024 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license. -->
 
 <link-summary>Layout and contents of a plugin distribution file.</link-summary>
 
 Plugin distribution will be built using [Gradle](tools_gradle_intellij_plugin.md#tasks-buildplugin) or [Plugin DevKit](deploying_theme.md).
 
-The plugin <path>.jar</path> file must contain:
+The plugin distribution <path>.jar</path> file contains:
 
-- the configuration file (<path>META-INF/plugin.xml</path>) ([Plugin Configuration File](plugin_configuration_file.md))
-- the classes that implement the plugin functionality
+- configuration file (<path>META-INF/plugin.xml</path>) ([Plugin Configuration File](plugin_configuration_file.md))
+- classes implementing the plugin functionality
 - recommended: plugin logo file(s) (<path>META-INF/pluginIcon*.svg</path>) ([Plugin Logo](plugin_icon_file.md))
 
-See [](plugin_user_experience.md#distribution-size) for important steps to optimize the plugin distribution file.
+> See [](plugin_user_experience.md#distribution-size) for important steps to optimize the plugin distribution file.
+
 
 Targeting a plugin distribution to a specific OS is not possible ([issue](https://youtrack.jetbrains.com/issue/MP-1896)).
 
@@ -20,17 +21,27 @@ Targeting a plugin distribution to a specific OS is not possible ([issue](https:
 
 A plugin consisting of a single <path>.jar</path> file is placed in the <path>/plugins</path> directory.
 
-```text
-.IntelliJIDEAx0/
-└── plugins
-    └── sample.jar
-        ├── com/company/sample/SamplePluginService.class
-        │   ...
-        │   ...
-        └── META-INF
-            ├── plugin.xml
-            ├── pluginIcon.svg
-            └── pluginIcon_dark.svg
+```plantuml
+@startuml
+
+skinparam TitleFontName JetBrains Sans
+skinparam TitleFontStyle plain
+skinparam TitleFontSize 16
+
+title
+|_ .IntelliJIDEAx0
+  |_ plugins
+    |_ sample.jar // (Plugin distribution) //
+      |_ com
+        |_ company
+          |_ Sample.class // (Class ""com.company.Sample"") //
+      |_ ...
+      |_ META-INF
+        |_ plugin.xml // (Plugin Configuration File) //
+        |_ pluginIcon.svg // (Plugin Logo) //
+        |_ pluginIcon_dark.svg // (Plugin Logo, dark variant) //
+end title
+@enduml
 ```
 
 ### Plugin With Dependencies
@@ -42,23 +53,32 @@ All jars from the <path>/lib</path> folder are automatically added to the classp
 > Do not repackage libraries into the main plugin archive (<path>sample.jar</path> in the sample below).
 > Otherwise, [Plugin Verifier](verifying_plugin_compatibility.md) will yield false positives for unresolved classes and methods.
 >
-{style="warning"}
+{title="Do Not Repackage Libraries" style="warning"}
 
-```text
-   .IntelliJIDEAx0/
-   └── plugins
-       └── sample
-           └── lib
-               ├── lib_foo.jar
-               ├── lib_bar.jar
-               │   ...
-               │   ...
-               └── sample.jar
-                   ├── com/company/sample/SamplePluginService.class
-                   │   ...
-                   │   ...
-                   └── META-INF
-                       ├── plugin.xml
-                       ├── pluginIcon.svg
-                       └── pluginIcon_dark.svg
+```plantuml
+@startuml
+
+skinparam TitleFontName JetBrains Sans
+skinparam TitleFontStyle plain
+skinparam TitleFontSize 16
+
+title
+|_ .IntelliJIDEAx0
+  |_ plugins
+    |_ sample
+      |_ lib
+        |_ lib_foo.jar // (Required bundled library #1) //
+        |_ lib_bar.jar // (Required bundled library #2) //
+        |_ ...
+        |_ sample.jar // (Plugin distribution) //
+          |_ com
+            |_ company
+              |_ Sample.class // (Class ""com.company.Sample"") //
+          |_ ...
+          |_ META-INF
+            |_ plugin.xml // (Plugin Configuration File) //
+            |_ pluginIcon.svg // (Plugin Logo) //
+            |_ pluginIcon_dark.svg // (Plugin Logo, dark variant) //
+end title
+@enduml
 ```