Associated pattern synonyms not included in haddock
Running haddock on:
```hs
{-# LANGUAGE PatternSynonyms #-}
module Foo ( A(P) ) where
data A a = A
pattern P = A
```
Just gives a data type A with no constructors, and no mention of the associated pattern synonym P.
Attached is a patch for haddock that prints associated patterns as GADT constructors
<details><summary>Trac metadata</summary>
| Trac field | Value |
| ---------------------- | ------------ |
| Version | 8.0.1-rc3 |
| Type | Bug |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | Compiler |
| Test case | |
| Differential revisions | |
| BlockedBy | |
| Related | |
| Blocking | |
| CC | |
| Operating system | |
| Architecture | |
</details>
<!-- {"blocked_by":[],"summary":"Associated pattern synonyms not included in haddock","status":"New","operating_system":"","component":"Compiler","related":[],"milestone":"8.0.1","resolution":"Unresolved","owner":{"tag":"Unowned"},"version":"8.0.1-rc3","keywords":[],"differentials":[],"test_case":"","architecture":"","cc":[""],"type":"Bug","description":"Running haddock on:\r\n\r\n{{{#!hs\r\n{-# LANGUAGE PatternSynonyms #-}\r\n\r\nmodule Foo ( A(P) ) where\r\n\r\ndata A a = A\r\n\r\npattern P = A\r\n}}}\r\n\r\nJust gives a data type A with no constructors, and no mention of the associated pattern synonym P.\r\n\r\nAttached is a patch for haddock that prints associated patterns as GADT constructors","type_of_failure":"OtherFailure","blocking":[]} -->
issue