src: consistently import HashMap as HM, Map as M

With both HashMap and Map imported as M in different modules,
linter rules prevented ever importing both modules in one place.

src/PostgREST/DbStructure/Proc.hs

@@ -15,7 +15,7 @@ module PostgREST.DbStructure.Proc
   ) where
 
 import qualified Data.Aeson          as JSON
-import qualified Data.HashMap.Strict as M
+import qualified Data.HashMap.Strict as HM
 
 import PostgREST.DbStructure.Identifiers (QualifiedIdentifier (..),
                                           Schema, TableName)
@@ -66,7 +66,7 @@ instance Ord ProcDescription where
 
 -- | A map of all procs, all of which can be overloaded(one entry will have more than one ProcDescription).
 -- | It uses a HashMap for a faster lookup.
-type ProcsMap = M.HashMap QualifiedIdentifier [ProcDescription]
+type ProcsMap = HM.HashMap QualifiedIdentifier [ProcDescription]
 
 procReturnsScalar :: ProcDescription -> Bool
 procReturnsScalar proc = case proc of

src/PostgREST/DbStructure/Relationship.hs

@@ -9,7 +9,7 @@ module PostgREST.DbStructure.Relationship
   ) where
 
 import qualified Data.Aeson          as JSON
-import qualified Data.HashMap.Strict as M
+import qualified Data.HashMap.Strict as HM
 
 import PostgREST.DbStructure.Identifiers (FieldName,
                                           QualifiedIdentifier, Schema)
@@ -53,4 +53,4 @@ data Junction = Junction
   deriving (Eq, Ord, Generic, JSON.ToJSON)
 
 -- | Key based on the source table and the foreign table schema
-type RelationshipsMap = M.HashMap (QualifiedIdentifier, Schema)  [Relationship]
+type RelationshipsMap = HM.HashMap (QualifiedIdentifier, Schema)  [Relationship]

src/PostgREST/DbStructure/Table.hs

@@ -8,7 +8,7 @@ module PostgREST.DbStructure.Table
   ) where
 
 import qualified Data.Aeson          as JSON
-import qualified Data.HashMap.Strict as M
+import qualified Data.HashMap.Strict as HM
 
 import PostgREST.DbStructure.Identifiers (FieldName,
                                           QualifiedIdentifier (..),
@@ -46,4 +46,4 @@ data Column = Column
   }
   deriving (Eq, Show, Ord, Generic, JSON.ToJSON)
 
-type TablesMap = M.HashMap QualifiedIdentifier Table
+type TablesMap = HM.HashMap QualifiedIdentifier Table