GH-666 Make init() of Position public

Why do I have to manually write a public init for a public struct?

NvimView/NvimView/Geometry.swift

@@ -20,6 +20,11 @@ public struct Position: CustomStringConvertible, Equatable {
   public var row: Int
   public var column: Int
 
+  public init(row: Int, column: Int) {
+    self.row = row
+    self.column = column
+  }
+
   public var description: String {
     return "Position<\(self.row):\(self.column)>"
   }