Document which default settings are changes, closes #672

Author: sheerun

README.md

@@ -254,13 +254,30 @@ This will not affect smart autoindenting when starting a new line.
 
 ## Default settings
 
-Vim Polyglot includes vim-sensible plugin, which is usually necessary for editing any language. This can be disabled with:
+Vim Polyglot sets defaults of some settings that are relevant for good language support. You can disable them by:
 
 
 ```vim
 let g:polyglot_disabled = ['sensible']
 ```
 
+These defaults include:
+- Use utf-8 encoding by default
+- Automatically reload file if changed somewhere else
+- Disable existing swapfile warnings, instead just create multiple swapfiles
+- Don't create swapfiles in current directory, instead in data directory
+- Whitespace characters when using `:set list`
+- Delete comment character when joining commented lines
+- Search upwards for tags file(s) instead only locally
+- Fix issues with fish shell
+- Increase history size to 1000 items
+- Allow for up to 50 opened tabs on Vim start.
+- Reduce updatetime from 4000 to 300 to avoid issues with coc.nvim
+- Always save upper case variables to viminfo file
+- Don't save options in sessions and views
+- Allow color schemes to do bright colors without forcing bold
+- Load vim's built-in matchit plugin
+
 ## No ftdetect
 
 If you want to use vim-polyglot plugins, but not ftdetect autocommands, the you can disable it as so: