Changing ToC indents

The docs.mbed can't see your indents, so the ToC is 27 flat items. It should be able to see these indents and given properly nested bullets.

Author: iriark01

README.md

@@ -10,27 +10,27 @@ This document covers the installation and usage of mbed CLI.
 1. [Installing and uninstalling](#installing-mbed-cli)
 1. [Understanding working context and program root](#before-you-begin-understanding-the-working-context-and-program-root)
 1. [Creating and importing programs](#creating-and-importing-programs)
-  1. [Creating a new program](#creating-a-new-program-for-mbed-os-5)
-  2. [Importing an existing program](#importing-an-existing-program)
+    1. [Creating a new program](#creating-a-new-program-for-mbed-os-5)
+    2. [Importing an existing program](#importing-an-existing-program)
 1. [Adding and removing libraries](#adding-and-removing-libraries)
 1. [Compiling code](#compiling-code)
-  1. [Toolchain selection](#toolchain-selection)
-  2. [Compiling your program](#compiling-your-program)
-  3. [Compiling static libraries](#compiling-static-libraries)
-  4. [Compile configuration system](#compile-configuration-system)
-  5. [Compile-time customizations](#compile-time-customizations)
+    1. [Toolchain selection](#toolchain-selection)
+    2. [Compiling your program](#compiling-your-program)
+    3. [Compiling static libraries](#compiling-static-libraries)
+    4. [Compile configuration system](#compile-configuration-system)
+    5. [Compile-time customizations](#compile-time-customizations)
 1. [Exporting to desktop IDEs](#exporting-to-desktop-ides)
 1. [Testing](#testing)
-  1. [Finding available tests](#finding-available-tests)
-  2. [Compiling and running tests](#compiling-and-running-tests)
-  3. [Limiting the test scope](#limiting-the-test-scope)
-  4. [Test directory structure](#test-directory-structure)
+    1. [Finding available tests](#finding-available-tests)
+    2. [Compiling and running tests](#compiling-and-running-tests)
+    3. [Limiting the test scope](#limiting-the-test-scope)
+    4. [Test directory structure](#test-directory-structure)
 1. [Publishing your changes](#publishing-your-changes)
-  1. [Checking status](#checking-status)
-  2. [Pushing upstream](#pushing-upstream)
+    1. [Checking status](#checking-status)
+    2. [Pushing upstream](#pushing-upstream)
 1. [Updating programs and libraries](#updating-programs-and-libraries)
-  1. [Updating to an upstream version](#updating-to-an-upstream-version)
-  2. [Update examples](#update-examples)
+    1. [Updating to an upstream version](#updating-to-an-upstream-version)
+    2. [Update examples](#update-examples)
 1. [mbed CLI configuration](#mbed-cli-configuration)
 1. [Troubleshooting](#troubleshooting)