Update keywords-and-maps.markdown (#1610)

Fixed a typo in document. Changed "convenienice" to "convenience"

Author: mockingbirdz

getting-started/keywords-and-maps.markdown

@@ -213,7 +213,7 @@ iex> if true do
 "This will be seen"
 ```
 
-It happens that `do` blocks are nothing more than a syntax convenienice on top of keywords. We can rewrite the above to:
+It happens that `do` blocks are nothing more than a syntax convenience on top of keywords. We can rewrite the above to:
 
 ```elixir
 iex> if true, do: "This will be seen", else: "This won't"
@@ -272,4 +272,4 @@ iex> users = update_in users[:mary].languages, fn languages -> List.delete(langu
 
 There is more to learn about `put_in/2` and `update_in/2`, including the `get_and_update_in/2` that allows us to extract a value and update the data structure at once. There are also `put_in/3`, `update_in/3` and `get_and_update_in/3` which allow dynamic access into the data structure. [Check their respective documentation in the `Kernel` module for more information](https://hexdocs.pm/elixir/Kernel.html).
 
-This concludes our introduction to associative data structures in Elixir. You will find out that, given keyword lists and maps, you will always have the right tool to tackle problems that require associative data structures in Elixir.
+This concludes our introduction to associative data structures in Elixir. You will find out that, given keyword lists and maps, you will always have the right tool to tackle problems that require associative data structures in Elixir.