small white write springboot project, configuration yml file no code prompt, tried a lot of online methods, but did not find the answer, finally accidentally solved. I hope my method can help you.
I used idea2020, which should be updated. The yml file icon in 2020 has been changed, and there are no green leaves. The specific icon is like this. 
if your icon looks like this, the software has recognized the yml file, but there is no code prompt, you need to download the yml plugin. Download plugins in setting. 
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