Fix introduction to the next topic in some pages, closes #15205

Author: josevalim

lib/elixir/pages/getting-started/enumerable-and-streams.md

@@ -110,4 +110,4 @@ The example above will fetch the first 10 lines of the file you have selected. T
 
 The `Enum` and `Stream` modules provide a wide range of functions, but you don't have to know all of them by heart. Familiarize yourself with `Enum.map/2`, `Enum.reduce/3` and other functions with either `map` or `reduce` in their names, and you will naturally build an intuition around the most important use cases. You may also focus on the `Enum` module first and only move to `Stream` for the particular scenarios where laziness is required, to either deal with slow resources or large, possibly infinite, collections.
 
-Next, we'll look at a feature central to Elixir, Processes, which allows us to write concurrent, parallel and distributed programs in an easy and understandable way.
+Next, we will look at an alternate approach of operating on collections: Comprehensions.

lib/elixir/pages/getting-started/io-and-the-file-system.md

@@ -206,3 +206,5 @@ We packed a lot into this small section, so let's break it down:
   * the choice between iodata and chardata depends on the encoding of the IO device. If the file is opened without encoding, the file expects iodata, and the functions in the `IO` module starting with `bin*` must be used. The default IO device (`:stdio`) and files opened with `:utf8` encoding expect chardata and work with the remaining functions in the `IO` module;
 
 This finishes our tour of IO devices and IO related functionality. We have learned about three Elixir modules - `IO`, `File`, and `Path` - as well as how the VM uses processes for the underlying IO mechanisms and how to use `chardata` and `iodata` for IO operations.
+
+Next we will talk about a very important subject to Elixir developers: writing documentation.

lib/elixir/pages/getting-started/try-catch-and-rescue.md

@@ -303,4 +303,6 @@ iex> try do
 ** (CompileError) undefined variable "another_what_happened"
 ```
 
-This finishes our introduction on `try`, `catch`, and `rescue`. You will find they are used less frequently in Elixir than in other languages. Next we will talk about a very important subject to Elixir developers: writing documentation.
+This finishes our introduction on `try`, `catch`, and `rescue`. You will find they are used less frequently in Elixir than in other languages.
+
+Next, we'll look at a feature central to Elixir, Processes, which allows us to write concurrent, parallel and distributed programs in an easy and understandable way.