Fix heading levels

README.md

@@ -166,21 +166,21 @@ stored in `%USERPROFILE%\_vimrc`.
 In Vim 8 and NeoVim, you can install plugins easily without needing to use
 any other tools. Simply clone the plugin into your `pack` directory.
 
-### Vim 8 on Unix
+#### Vim 8 on Unix
 
 ```bash
 mkdir -p ~/.vim/pack/git-plugins/start
 git clone https://github.com/w0rp/ale.git ~/.vim/pack/git-plugins/start/ale
 ```
 
-### NeoVim on Unix
+#### NeoVim on Unix
 
 ```bash
 mkdir -p ~/.local/share/nvim/site/pack/git-plugins/start
 git clone https://github.com/w0rp/ale.git ~/.local/share/nvim/site/pack/git-plugins/start/ale
 ```
 
-### Vim 8 on Windows
+#### Vim 8 on Windows
 
 ```bash
 # Run these commands in the "Git for Windows" Bash terminal
@@ -188,7 +188,7 @@ mkdir -p ~/vimfiles/pack/git-plugins/start
 git clone https://github.com/w0rp/ale.git ~/vimfiles/pack/git-plugins/start/ale
 ```
 
-### Generating documentation
+#### Generating documentation
 
 You can add the following line to your vimrc files to generate documentation
 tags automatically, if you don't have something similar already, so you can use