Add qnames for Haskell

Summary:
One of the most common errors on API Docs appears to be

```
ServerException	ServerException {serverException_message = "QualifiedName: Language unsupported: Language_Haskell"}	247 (0.4%)
```

247 events in the last day.

I don't fully understand how it could be so common, unless Haskell api pages are getting rendered in search results somewhere and failing.

Somewhere along the line qnames became mandatory, instead of optional. So fix that.

also fixes search : "No results found in symbol"

in search, Haskell syms are still only discoverable by qname
{F1761495551}

the underlying problem is the hs.DefinitionName is a qname

we need a dotted form with separate structured components.

```
fbsource.fbcode.haskell> hs.DefinitionName _
{ "id": 88131, "key": "A.Types.A" }
{ "id": 61435, "key": "A.a" }
{ "id": 68899, "key": "A.main" }
{ "id": 82260, "key": "AardvarkTest.aardvarkCounter" }
{ "id": 82262, "key": "AardvarkTest.main" }
{ "id": 91585, "key": "Acl.Types.Identity" }
{ "id": 52655, "key": "AddPrefixTest.main" }
{ "id": 52661, "key": "AddPrefixTest.toPrefixedE" }
{ "id": 52659, "key": "AddPrefixTest.toPrefixedS" }
{ "id": 52657, "key": "AddPrefixTest.toPrefixedU" }
{ "id": 75973, "key": "AesonTest.main" }
{ "i
```

becomes:

Reviewed By: simonmar

Differential Revision: D59898073

fbshipit-source-id: 5f1851ca5350edf6d5ab60119be66da5feb1f7f8

glean/glass/Glean/Glass/SymbolId.hs

@@ -387,6 +387,7 @@ instance ToQName Code.Entity where
     Code.Entity_flow x -> toQName x
     Code.Entity_graphql x -> toQName x
     Code.Entity_hack (Hack.Entity_decl x) -> toQName x
+    Code.Entity_hs x -> toQName x
     Code.Entity_java x -> toQName x
     Code.Entity_kotlin x -> toQName x
     Code.Entity_pp x -> toQName x

glean/glass/Glean/Glass/SymbolId/Hs.hs

@@ -9,16 +9,22 @@
 {-# OPTIONS_GHC -Wno-orphans #-}
 
 module Glean.Glass.SymbolId.Hs ({- instances -}) where
+
+import Data.Text (Text)
 import qualified Data.Text as Text
-import Glean.Glass.SymbolId.Class
-    ( toSymbolPredicate, Symbol(..) )
 
+import Glean.Glass.SymbolId.Class
+import Glean.Glass.Types (Name(..))
+import Glean.Schema.CodeHs.Types as Hs (Entity (..))
 import qualified Glean
-
 import qualified Glean.Schema.Hs.Types as Hs
 import qualified Glean.Schema.Src.Types as Src
 
-import Glean.Schema.CodeHs.Types as Hs (Entity (..))
+instance Symbol Hs.Entity where
+  toSymbol (Hs.Entity_definition d) = toSymbolPredicate d
+  toSymbol (Hs.Entity_function_ d) = toSymbolPredicate d
+  toSymbol (Hs.Entity_class_ d) = toSymbolPredicate d
+  toSymbol Hs.Entity_EMPTY = return []
 
 instance Symbol Hs.Definition_key where
   toSymbol (Hs.Definition_key name _) = do
@@ -37,8 +43,37 @@ instance Symbol Hs.Class_key where
     fname <- Glean.keyOf range_file
     return (fname : Text.splitOn "." name)
 
-instance Symbol Hs.Entity where
-  toSymbol (Hs.Entity_definition d) = toSymbolPredicate d
-  toSymbol (Hs.Entity_function_ d) = toSymbolPredicate d
-  toSymbol (Hs.Entity_class_ d) = toSymbolPredicate d
-  toSymbol Hs.Entity_EMPTY = return []
+instance ToQName Hs.Entity where
+  toQName (Hs.Entity_definition d) = Glean.keyOf d >>= toQName
+  toQName (Hs.Entity_function_ d) = Glean.keyOf d >>= toQName
+  toQName (Hs.Entity_class_ d) = Glean.keyOf d >>= toQName
+  toQName Hs.Entity_EMPTY =
+    return $ Left "toQName: Haskell: empty qname"
+
+instance ToQName Hs.Definition_key where
+  toQName (Hs.Definition_key name _) = do
+    n <- Glean.keyOf name
+    return $ case reverse (Text.splitOn "." n) of
+      [] -> Left "toQName: Haskell: empty function qname"
+      [x] -> Right (Name x, Name "")
+      (x:xs) -> Right (Name x, joinDotted xs)
+
+instance ToQName Hs.FunctionDefinition_key where
+  toQName (Hs.FunctionDefinition_key fnName Src.Range{..}) = do
+    name <- Glean.keyOf fnName
+    return $ case reverse (Text.splitOn "." name) of
+      [] -> Left "toQName: Haskell: empty function qname"
+      [x] -> Right (Name x, Name "")
+      (x:xs) -> Right (Name x, joinDotted xs)
+
+
+instance ToQName Hs.Class_key where
+  toQName (Hs.Class_key clsName Src.Range{..}) = do
+    name <- Glean.keyOf clsName
+    return $ case reverse (Text.splitOn "." name) of
+      [] -> Left "toQName: Haskell: empty class qname"
+      [x] -> Right (Name x, Name "")
+      (x:xs) -> Right (Name x, joinDotted xs)
+
+joinDotted :: [Text] -> Name
+joinDotted = Name . Text.intercalate "." . reverse