Use codespell (plausible#4145)

* Fix typos

* Add .codespellignore

* Add codespell GH action

.codespellignore

@@ -0,0 +1,8 @@
+caf
+Linz
+linz
+Taht
+taht
+referer
+referers
+

.github/workflows/codespell.yml

@@ -0,0 +1,17 @@
+name: Check spelling
+
+on:
+  pull_request:
+  push:
+    branches: [ master ]
+
+jobs:
+  codespell:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: codespell-project/actions-codespell@v2
+      with:
+        check_filenames: true
+        ignore_words_file: .codespellignore
+        path: lib test extra 

lib/plausible/funnel/const.ex

@@ -1,6 +1,6 @@
 defmodule Plausible.Funnel.Const do
   @moduledoc """
-  Compile-time convience constants for funnel characteristics.
+  Compile-time convenience constants for funnel characteristics.
   """
   @min_steps 2
   @max_steps 8

test/plausible/pagination_test.exs

@@ -31,7 +31,7 @@ defmodule Plausible.PaginationTest do
     assert Enum.count(pagination.entries) == Enum.count(sites)
   end
 
-  test "user provided limit exceeeds maximum limit", %{query: q} do
+  test "user provided limit exceeds maximum limit", %{query: q} do
     pagination = Pagination.paginate(q, %{"limit" => 200}, cursor_fields: [id: :desc])
     assert pagination.metadata.limit == 10
   end

test/plausible_web/controllers/auth_controller_test.exs

@@ -1112,7 +1112,7 @@ defmodule PlausibleWeb.AuthControllerTest do
       assert team_member_usage_row_text == "Team members 0"
     end
 
-    test "redners 2FA section in disabled state", %{conn: conn} do
+    test "renders 2FA section in disabled state", %{conn: conn} do
       conn = get(conn, "/settings")
 
       assert html_response(conn, 200) =~ "Enable 2FA"

test/plausible_web/controllers/google_analytics_controller_test.exs

@@ -172,7 +172,7 @@ defmodule PlausibleWeb.GoogleAnalyticsControllerTest do
                "Google Analytics API has timed out."
     end
 
-    test "redirects to imports and exports on list retrival failure with flash error",
+    test "redirects to imports and exports on list retrieval failure with flash error",
          %{
            conn: conn,
            site: site

test/plausible_web/controllers/site_controller_test.exs

@@ -756,7 +756,7 @@ defmodule PlausibleWeb.SiteControllerTest do
 
     setup tags do
       if tags[:async] do
-        raise "this test modifies application envinronment and can't be run asynchronously"
+        raise "this test modifies application environment and can't be run asynchronously"
       end
 
       prev_env = Application.get_env(:ex_aws, :s3)
@@ -1556,7 +1556,7 @@ defmodule PlausibleWeb.SiteControllerTest do
       assert is_nil(site.domain_changed_from)
     end
 
-    test "domain change succcessful form submission redirects to snippet change info", %{
+    test "domain change successful form submission redirects to snippet change info", %{
       conn: conn,
       site: site
     } do