Replace backpassing with ?

Author: ageron

examples/getVisualWidth.roc

@@ -4,6 +4,7 @@ app [main] {
 }
 
 import pf.Stdout
+import pf.Task exposing [Task]
 import unicode.CodePoint
 
 word = "世界"

examples/nrOfCodePoints.roc

@@ -4,7 +4,7 @@ app [main] {
 }
 
 import pf.Stdout
-import pf.Task
+import pf.Task exposing [Task]
 import unicode.CodePoint exposing [Utf8ParseErr]
 
 ## Get the number of code points for a given Str

package/Grapheme.roc

@@ -30,14 +30,11 @@ split = \str ->
     # I'm not sure if we should return an error here or just crash.
     # A Roc Str should be be valid utf8 and so in theory it should not be possible
     # for split to have invalid utf8 in it. To be discussed.
-    str
-    |> Str.toUtf8
-    |> CodePoint.parseUtf8
-    |> Result.map \codePoints ->
+    codePoints = str |> Str.toUtf8 |> CodePoint.parseUtf8?
 
-        breakPoints = codePoints |> List.map InternalGBP.fromCP
+    breakPoints = codePoints |> List.map InternalGBP.fromCP
 
-        splitHelp Next codePoints breakPoints [BR GB1] |> toListStr
+    Ok (splitHelp Next codePoints breakPoints [BR GB1] |> toListStr)
 
 # Used internally to filter out the break/nobreak tokens and separate CPs into a List Str
 toListStr : Tokens -> List Str