Change infix patterns to include spaces

This commit changes infix patterns to utilize `lrdrNameToTextAnn`. This
function allows the logic to avoid introspecting on the constructor
name.

Additionally this adds spaces to all infix operator pattern matches.
Previously infix symbols did not include spaces:

```
foo (x:xs) = _
```

Now they include a space

```
foo (x : xs) = _
```

src-literatetests/10-tests.blt

@@ -349,11 +349,11 @@ func reallyreallyreallyreallyreallyreallyreallyreallyreallyreallylongvariable
 func (A a) = a
 
 #test list constructor
-func (x:xr) = x
+func (x : xr) = x
 
 #test some other constructor symbol
 #pending
-func (x:+:xr) = x
+func (x :+: xr) = x
 
 #test normal infix constructor
 func (x `Foo` xr) = x

src-literatetests/15-regressions.blt

@@ -123,7 +123,7 @@ func = do
 #test list comprehension comment placement
 func =
   [ (thing, take 10 alts) --TODO: select best ones
-  | (thing, _got, alts@(_:_)) <- nosuchFooThing
+  | (thing, _got, alts@(_ : _)) <- nosuchFooThing
   , gast                        <- award
   ]
 

src-literatetests/tests-context-free.blt

@@ -366,11 +366,11 @@ func reallyreallyreallyreallyreallyreallyreallyreallyreallyreallylongvariable
 func (A a) = a
 
 #test list constructor
-func (x:xr) = x
+func (x : xr) = x
 
 #test some other constructor symbol
 #pending
-func (x:+:xr) = x
+func (x :+: xr) = x
 
 
 ###############################################################################
@@ -748,7 +748,7 @@ func = do
 #test list comprehension comment placement
 func =
   [ (thing, take 10 alts) --TODO: select best ones
-  | (thing, _got, alts@(_:_)) <- nosuchFooThing
+  | (thing, _got, alts@(_ : _)) <- nosuchFooThing
   , gast <- award
   ]
 

src/Language/Haskell/Brittany/Internal/Layouters/Pattern.hs

@@ -78,12 +78,10 @@ layoutPat lpat@(L _ pat) = docWrapNode lpat $ case pat of
         return $ x1 Seq.<| xR
   ConPatIn lname (InfixCon left right) -> do
     -- a :< b -> expr
-    let nameDoc = lrdrNameToText lname
-    leftDoc  <- colsWrapPat =<< layoutPat left
+    let nameDoc = lrdrNameToTextAnn lname
+    leftDoc  <- appSep . colsWrapPat =<< layoutPat left
     rightDoc <- colsWrapPat =<< layoutPat right
-    middle <- docLit $ if Text.any isAlpha nameDoc
-      then Text.pack " `" <> nameDoc <> Text.pack "` "
-      else nameDoc
+    middle <- appSep . docLit =<< nameDoc
     return $ Seq.empty Seq.|> leftDoc Seq.|> middle Seq.|> rightDoc
   ConPatIn lname (RecCon (HsRecFields [] Nothing)) -> do
     -- Abc{} -> expr