How do I name a theme file for view? I am trying to theme a block from my view.  I have a view called slides and it is creating a block.  I have a template file I want this block to use.  I have looked at the documentation for themes and the pattern to follow is

views-block--&lt;viewname&gt;.html.twig


or

block--views-block--&lt;viewname&gt;-displayid.html.twig


I can't find displayid for my block so I am trying to get that first option to work, but No matter what I do my block wont seem to take on the template I have written.

my template is named 

views-block--slideshow.html.twig


What am I doing wrong with my names?
In your development.services.yaml file set twig debug to true and disable the cache by setting value to false.

After that you will see theme suggestions by inspecting element in browser.