Colon always needs space around

Reverts 9284f1a which adds space around colons only in the case of
ternary expressions. However, import bindings and class inheritance
needs space as well. The overhead of the ast-list techniques seems
unnecessary.

src/dfmt.d

@@ -313,17 +313,6 @@ private:
             case tok!"(":
                 writeParens(true);
                 break;
-            case tok!":":
-                if (!assumeSorted(astInformation.ternaryColonLocations)
-                    .equalRange(current.index).empty)
-                {
-                    write(" ");
-                    writeToken();
-                    write(" ");
-                }
-                else
-                    writeToken();
-                break;
             case tok!"@":
             case tok!"!":
             case tok!"...":
@@ -333,6 +322,10 @@ private:
             case tok!"$":
                 writeToken();
                 break;
+            case tok!":":
+                write(" : ");
+                index += 1;
+                break;
             case tok!"]":
                 writeToken();
                 if (current.type == tok!"identifier")
@@ -811,9 +804,6 @@ struct ASTInformation
 
     /// Locations of unary operators
     size_t[] unaryLocations;
-
-    /// Locations of ':' operators in ternary expressions
-    size_t[] ternaryColonLocations;
 }
 
 /// Collects information from the AST that is useful for the formatter
@@ -886,13 +876,6 @@ final class FormatVisitor : ASTVisitor
         unary.accept(this);
     }
 
-    override void visit(const TernaryExpression ternary)
-    {
-        if (ternary.colon.type != tok!"")
-            astInformation.ternaryColonLocations ~= ternary.colon.index;
-        ternary.accept(this);
-    }
-
 private:
     ASTInformation* astInformation;
     alias visit = ASTVisitor.visit;