chore: improve adapters docs

lib/tesla/adapter/finch.ex

@@ -6,7 +6,7 @@ if Code.ensure_loaded?(Finch) do
     Remember to add `{:finch, "~> 0.14.0"}` to dependencies. Also, you need to
     recompile tesla after adding the `:finch` dependency:
 
-    ```
+    ```shell
     mix deps.clean tesla
     mix compile
     ```
@@ -24,15 +24,15 @@ if Code.ensure_loaded?(Finch) do
 
     You must provide the same name to this adapter:
 
-    ```
+    ```elixir
     # set globally in config/config.exs
     config :tesla, :adapter, {Tesla.Adapter.Finch, name: MyFinch}
 
     # set per module
     defmodule MyClient do
-      use Tesla
-
-      adapter Tesla.Adapter.Finch, name: MyFinch
+      def client do
+        Tesla.client([], {Tesla.Adapter.Finch, name: MyFinch})
+      end
     end
     ```
 

lib/tesla/adapter/gun.ex

@@ -8,21 +8,22 @@ if Code.ensure_loaded?(:gun) do
     In version 1.3 gun sends `host` header with port. Fixed in master branch.
     Also, you need to recompile tesla after adding `:gun` dependency:
 
-    ```
+    ```shell
     mix deps.clean tesla
     mix deps.compile tesla
     ```
 
     ## Examples
 
-    ```
+    ```elixir
     # set globally in config/config.exs
     config :tesla, :adapter, Tesla.Adapter.Gun
 
     # set per module
     defmodule MyClient do
-      use Tesla
-      adapter Tesla.Adapter.Gun
+      def client do
+        Tesla.client([], Tesla.Adapter.Gun)
+      end
     end
     ```
 

lib/tesla/adapter/hackney.ex

@@ -6,22 +6,22 @@ if Code.ensure_loaded?(:hackney) do
     Remember to add `{:hackney, "~> 1.13"}` to dependencies (and `:hackney` to applications in `mix.exs`)
     Also, you need to recompile tesla after adding `:hackney` dependency:
 
-    ```
+    ```shell
     mix deps.clean tesla
     mix deps.compile tesla
     ```
 
     ## Examples
 
-    ```
+    ```elixir
     # set globally in config/config.exs
     config :tesla, :adapter, Tesla.Adapter.Hackney
 
     # set per module
     defmodule MyClient do
-      use Tesla
-
-      adapter Tesla.Adapter.Hackney
+      def client do
+        Tesla.client([], Tesla.Adapter.Hackney)
+      end
     end
     ```
 

lib/tesla/adapter/ibrowse.ex

@@ -6,22 +6,22 @@ if Code.ensure_loaded?(:ibrowse) do
     Remember to add `{:ibrowse, "~> 4.2"}` to dependencies (and `:ibrowse` to applications in `mix.exs`)
     Also, you need to recompile tesla after adding `:ibrowse` dependency:
 
-    ```
+    ```elixir
     mix deps.clean tesla
     mix deps.compile tesla
     ```
 
     ## Examples
 
-    ```
+    ```elixir
     # set globally in config/config.exs
     config :tesla, :adapter, Tesla.Adapter.Ibrowse
 
     # set per module
     defmodule MyClient do
-      use Tesla
-
-      adapter Tesla.Adapter.Ibrowse
+      def client do
+        Tesla.client([], Tesla.Adapter.Ibrowse)
+      end
     end
     ```
     """

lib/tesla/adapter/mint.ex

@@ -8,20 +8,21 @@ if Code.ensure_loaded?(Mint.HTTP) do
     Remember to add `{:mint, "~> 1.0"}` and `{:castore, "~> 0.1"}` to dependencies.
     Also, you need to recompile tesla after adding `:mint` dependency:
 
-    ```
+    ```shell
     mix deps.clean tesla
     mix deps.compile tesla
     ```
 
     ## Examples
 
-    ```
+    ```elixir
     # set globally in config/config.exs
     config :tesla, :adapter, Tesla.Adapter.Mint
     # set per module
     defmodule MyClient do
-      use Tesla
-      adapter Tesla.Adapter.Mint
+      def client do
+        Tesla.client([], Tesla.Adapter.Mint)
+      end
     end
 
     # set global custom cacertfile