CONTRIBUTING.md: fix "Images" sample formatting
CONTRIBUTING.md: fix "Images" sample formatting

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