message: Update OBJC-HOWTO.md
diff: This document contains instructions and Obj-C code snippets for common tasks in
  [Tink](https://github.com/google/tink).
  -## Setup intructions
  +## Setup instructions
  Tink is released as a [Cocoapod](https://cocoapods.org/). It can be installed by
  using the pod command as described below, which is the recommended way to use
  @@ -296,7 +296,7 @@ that specifies what operations are offered by the primitive. A primitive can
  have multiple implementations, and you choose a desired implementation by using
  a key of corresponding type (see the [this
  section](KEY-MANAGEMENT.md#key-keyset-and-keysethandle) for details). A list of
  -primitives and their implemenations currently supported by Tink in Objective-C
  +primitives and their implementations currently supported by Tink in Objective-C
  can be found [here](PRIMITIVES.md#objective-c).
  You access implementations of a primitive via a factory that corresponds to the
  