Change getNextId to create a zero width span at new id

src/ShellCheck/Parser.hs

@@ -185,8 +185,9 @@ getNextIdAt sourcepos = do
 
 getNextId :: Monad m => SCParser m Id
 getNextId = do
-    pos <- getPosition
-    getNextIdAt pos
+    start <- startSpan
+    id <- endSpan start
+    return id
 
 data IncompleteInterval = IncompleteInterval SourcePos
 
@@ -204,11 +205,6 @@ endSpan (IncompleteInterval start) = do
     }
     return id
 
-zeroWidthSpan = do
-    start <- startSpan
-    id <- endSpan start
-    return id
-
 addToHereDocMap id list = do
     state <- getState
     let map = hereDocMap state