Add Shared Preferences plugin docs

Summary: Moar docz

Reviewed By: danielbuechele

Differential Revision: D8752565

fbshipit-source-id: d7e4392e00dc06b0ffbebce491d5244b4b31a34d

docs/shared-preferences-plugin.md

@@ -0,0 +1,25 @@
+---
+id: shared-preferences-plugin
+title: Shared Preferences
+---
+
+Easily inspect and modify the data contained within your app's shared preferences.
+
+![Shared Preferences Plugin](/docs/assets/shared-preferences.png)
+
+## Setup
+
+Note: this plugin is only available for Android.
+
+### Android
+
+```java
+import com.facebook.sonar.plugins.sharedpreferences.SharedPreferencesSonarPlugin;
+
+client.addPlugin(
+    new SharedPreferencesSonarPlugin(context, "my_shared_preference_file"));
+```
+
+## Usage
+
+All changes to the given shared preference file will automatically appear in Sonar. You may also edit the values in Sonar and have them synced to your device. This can be done by clicking on the value of the specific key you wish to edit, editing the value and then pressing enter.

website/i18n/en.json

@@ -19,8 +19,10 @@
     "layout-plugin": "Layout Inspector",
     "logs-plugin": "Logs",
     "network-plugin": "Network",
+    "sandbox-plugin": "Sandbox",
     "send-data": "Sending Data to Plugins",
     "Send Data": "Send Data",
+    "shared-preferences-plugin": "Shared Preferences",
     "stetho": "Stetho Guidance",
     "Stetho Guidance": "Stetho Guidance",
     "styling-components": "Styling Components",

website/sidebars.json

@@ -5,7 +5,8 @@
       "logs-plugin",
       "layout-plugin",
       "network-plugin",
-      "sandbox-plugin"
+      "sandbox-plugin",
+      "shared-preferences-plugin"
     ],
     "Plugins: Desktop part": [
       "js-setup",