Fix MRF documentation

docs/configuration/mrf.md

@@ -1,4 +1,5 @@
 # Message Rewrite Facility
+
 The Message Rewrite Facility (MRF) is a subsystem that is implemented as a series of hooks that allows the administrator to rewrite or discard messages.
 
 Possible uses include:
@@ -10,7 +11,8 @@ Possible uses include:
 * removing media from messages
 * sending only public messages to a specific instance
 
-The MRF provides user-configurable policies.  The default policy is `NoOpPolicy`, which disables the MRF functionality.  Pleroma also includes an easy to use policy called `SimplePolicy` which maps messages matching certain pre-defined criterion to actions built into the policy module.
+The MRF provides user-configurable policies. The default policy is `NoOpPolicy`, which disables the MRF functionality. Pleroma also includes an easy to use policy called `SimplePolicy` which maps messages matching certain pre-defined criterion to actions built into the policy module.
+
 It is possible to use multiple, active MRF policies at the same time.
 
 ## Quarantine Instances
@@ -18,7 +20,8 @@ It is possible to use multiple, active MRF policies at the same time.
 You have the ability to prevent from private / followers-only messages from federating with specific instances. Which means they will only get the public or unlisted messages from your instance.
 
 If, for example, you're using `MIX_ENV=prod` aka using production mode, you would open your configuration file located in `config/prod.secret.exs` and edit or add the option under your `:instance` config object. Then you would specify the instance within quotes.
-```
+
+```elixir
 config :pleroma, :instance,
   [...]
   quarantined_instances: ["instance.example", "other.example"]
@@ -28,15 +31,15 @@ config :pleroma, :instance,
 
 `SimplePolicy` is capable of handling most common admin tasks.
 
-To use `SimplePolicy`, you must enable it.  Do so by adding the following to your `:instance` config object, so that it looks like this:
+To use `SimplePolicy`, you must enable it. Do so by adding the following to your `:instance` config object, so that it looks like this:
 
-```
+```elixir
 config :pleroma, :instance,
   [...]
   rewrite_policy: Pleroma.Web.ActivityPub.MRF.SimplePolicy
 ```
 
-Once `SimplePolicy` is enabled, you can configure various groups in the `:mrf_simple` config object.  These groups are:
+Once `SimplePolicy` is enabled, you can configure various groups in the `:mrf_simple` config object. These groups are:
 
 * `media_removal`: Servers in this group will have media stripped from incoming messages.
 * `media_nsfw`: Servers in this group will have the #nsfw tag and sensitive setting injected into incoming messages which contain media.
@@ -50,7 +53,7 @@ Servers should be configured as lists.
 
 This example will enable `SimplePolicy`, block media from `illegalporn.biz`, mark media as NSFW from `porn.biz` and `porn.business`, reject messages from `spam.com`, remove messages from `spam.university` from the federated timeline and block reports (flags) from `whiny.whiner`:
 
-```
+```elixir
 config :pleroma, :instance,
   rewrite_policy: [Pleroma.Web.ActivityPub.MRF.SimplePolicy]
 
@@ -60,16 +63,15 @@ config :pleroma, :mrf_simple,
   reject: ["spam.com"],
   federated_timeline_removal: ["spam.university"],
   report_removal: ["whiny.whiner"]
-
 ```
 
 ### Use with Care
 
-The effects of MRF policies can be very drastic.  It is important to use this functionality carefully.  Always try to talk to an admin before writing an MRF policy concerning their instance.
+The effects of MRF policies can be very drastic. It is important to use this functionality carefully. Always try to talk to an admin before writing an MRF policy concerning their instance.
 
 ## Writing your own MRF Policy
 
-As discussed above, the MRF system is a modular system that supports pluggable policies.  This means that an admin may write a custom MRF policy in Elixir or any other language that runs on the Erlang VM, by specifying the module name in the `rewrite_policy` config setting.
+As discussed above, the MRF system is a modular system that supports pluggable policies. This means that an admin may write a custom MRF policy in Elixir or any other language that runs on the Erlang VM, by specifying the module name in the `rewrite_policy` config setting.
 
 For example, here is a sample policy module which rewrites all messages to "new message content":
 
@@ -83,7 +85,7 @@ defmodule Site.RewritePolicy do
   # Capture the object as `object`, the message content as `content` and the
   # message itself as `message`.
   @impl true
-  def filter(%{"type" => Create", "object" => {"type" => "Note", "content" => content} = object} = message)
+  def filter(%{"type" => "Create", "object" => {"type" => "Note", "content" => content} = object} = message)
       when is_binary(content) do
     # Subject / CW is stored as summary instead of `name` like other AS2 objects
     # because of Mastodon doing it that way.
@@ -109,9 +111,9 @@ defmodule Site.RewritePolicy do
 end
 ```
 
-If you save this file as `lib/site/mrf/rewrite_policy.ex`, it will be included when you next rebuild Pleroma.  You can enable it in the configuration like so:
+If you save this file as `lib/site/mrf/rewrite_policy.ex`, it will be included when you next rebuild Pleroma. You can enable it in the configuration like so:
 
-```
+```elixir
 config :pleroma, :instance,
   rewrite_policy: [
     Pleroma.Web.ActivityPub.MRF.SimplePolicy,
@@ -119,4 +121,4 @@ config :pleroma, :instance,
   ]
 ```
 
-Please note that the Pleroma developers consider custom MRF policy modules to fall under the purview of the AGPL.  As such, you are obligated to release the sources to your custom MRF policy modules upon request.
+Please note that the Pleroma developers consider custom MRF policy modules to fall under the purview of the AGPL. As such, you are obligated to release the sources to your custom MRF policy modules upon request.