Fix typos on documentation (#24)

Found via `typos --hidden --format brief`

Author: kianmeng

README.md

@@ -1,6 +1,6 @@
 # ErrorTracker
 
-En Elixir based built-in error tracking solution.
+An Elixir based built-in error tracking solution.
 
 <a href="guides/screenshots/error-dashboard.png">
   <img src="guides/screenshots/error-dashboard.png" alt="ErrorTracker web dashboard" width="400">
@@ -27,7 +27,7 @@ iex -S mix dev
 
 ### Assets
 
-In ortder to participate in the development of this library, you may need to
+In order to participate in the development of this library, you may need to
 know how to compile the assets needed to use the Web UI.
 
 To do so, you need to first make a clean build:

lib/error_tracker.ex

@@ -161,7 +161,7 @@ defmodule ErrorTracker do
   You can store context on more than one level of depth, but take into account
   that the merge operation is performed on the first level.
 
-  That means that any existing data on deep levels fot he current context will
+  That means that any existing data on deep levels for he current context will
   be replaced if the first level key is received on the new contents.
   """
   @spec set_context(context()) :: context()

lib/error_tracker/integrations/oban.ex

@@ -17,7 +17,7 @@ defmodule ErrorTracker.Integrations.Oban do
   By default we store some context for you on errors generated in an Oban
   process:
 
-  * `job.id`: the unqiue ID of the job.
+  * `job.id`: the unique ID of the job.
 
   * `job.worker`: the name of the worker module.
 
@@ -37,7 +37,7 @@ defmodule ErrorTracker.Integrations.Oban do
   ]
 
   @doc """
-  Attachs to Oban's Telemetry events if the library is detected.
+  Attaches to Oban's Telemetry events if the library is detected.
 
   This function is usually called internally during the startup process so you
   don't have to.

lib/error_tracker/integrations/phoenix.ex

@@ -64,7 +64,7 @@ defmodule ErrorTracker.Integrations.Phoenix do
   ]
 
   @doc """
-  Attachs to Phoenix's Telemetry events if the library is detected.
+  Attaches to Phoenix's Telemetry events if the library is detected.
 
   This function is usually called internally during the startup process so you
   don't have to.