Steps:
1. Add "GameObject -> Effects -> Particle System" GameObject to Hierarchy
2. Create a script in Project browser
3. Select Particle System prefab instance in the Hierarchy
4. Drag and drop the script from Project browser above "Add component" button in Inspector
==>
Particle System Renderer component appears in the Inspector window as well (it should be hidden as its UI is integrated in the Particle System's modules)

Note that if you deselect and select the ParticleSystem again the Inspector shows the correct Editors (The PSR is now hidden)

Reproduced in 19.3 and 19.2