Add option to force disable SMEI_UNIFIED_PROFILES

Proposed here:
https://groups.google.com/g/twpowertools-discuss/c/QSOXU8IbrYU

Fixes: #47
Change-Id: I05caf5248cec1121ee083362910f81c484bfb3b2
diff --git a/docs/features.md b/docs/features.md
index 75a8d57..8fa27ba 100644
--- a/docs/features.md
+++ b/docs/features.md
@@ -3,6 +3,8 @@
 # Features
 The TW Power Tools extension offers the following features/options:
 
+[TOC]
+
 ## Infinite scroll
 ### Thread lists
 > **Option name:** _Enable infinite scrolling in thread lists_.
@@ -128,7 +130,25 @@
 
 ![Picture showing the feature](resources/reposition_expand_thread.jpg)
 
-### Indicator dot
+### Go back to the old profile view
+> **Option name:** _Force disable the `SMEI_UNIFIED_PROFILES` experiment in the
+Community Console._
+
+This option disables the `SMEI_UNIFIED_PROFILES` experiment, which when enabled
+introduces a redesign of the profile view which also unifies all forum profiles
+into a single one.
+
+This means that independently of whether your account is part of this
+experiment, when enabling this option the experiment will be forced disabled
+and you'll continue to see the old/regular profile view, which shows user
+profiles in a per-forum basis.
+
+Note that this only applies to the Community Console.
+
+This might be useful if you're using the dark theme, since the new unified
+profiles haven't been yet adapted to the dark theme.
+
+## Indicator dot
 > **Option names:** _Show whether the OP has participated in other threads_,
 _Show the number of questions and replies written by the OP within the last `n`
 months next to their username_.