Update 'working with intellij' readme and commit additional metadata.

client/idea/readme.md

Index: client/idea/readme.md
diff --git a/client/idea/readme.md b/client/idea/readme.md
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--- a/client/idea/readme.md
+++ b/client/idea/readme.md
@@ -1,5 +1,20 @@
-To open the sdk repo using IntelliJ, you can:
+# Working on the SDK repo using IntelliJ
 
-- choose `File` > `Open...`, and select the <sdk>/client/idea directory
-- or, from the CLI, type: `idea <sdk>client/idea` (for this to work you need to
-  set up an IntelliJ command-line launcher)
+To work on Dart code in the SDK repo, we recommend either IntelliJ Community
+Edition or IntelliJ Ultimate.
+
+## Opening from IntelliJ
+
+To open the sdk repo using IntelliJ, choose `File` > `Open...` and select the
+`<sdk>/client/idea` directory.
+
+## Opening from the command-line
+
+To open from the command-line, type:
+
+```
+idea <sdk>/client/idea
+```
+
+This depends on having previously set up the IntelliJ command-line launcher. To
+do this, from the `Tools` menu, select `Create Command-line Launcher...`.