writing_tests_for_plugins.md: cleanup
writing_tests_for_plugins.md: cleanup

artspb/intellij-sdk-docs,artspb/intellij-sdk-docs,artspb/intellij-sdk-docs,JetBrains/intellij-sdk-docs,JetBrains/intellij-sdk-docs,artspb/intellij-sdk-docs,JetBrains/intellij-sdk-docs