Drop `X-UA-Compatible` header usage as per IE deprecation

Ref https://github.com/h5bp/server-configs-apache/issues/210
Ref https://github.com/h5bp/server-configs-apache/issues/182

h5bp/basic.conf

@@ -1,7 +1,6 @@
 # Nginx Server Configs | MIT License
 # https://github.com/h5bp/server-configs-nginx
 
-include h5bp/internet_explorer/x-ua-compatible.conf;
 include h5bp/security/referrer-policy.conf;
 include h5bp/security/x-content-type-options.conf;
 include h5bp/security/x-frame-options.conf;

h5bp/internet_explorer/x-ua-compatible.conf

@@ -1,19 +0,0 @@
-# ----------------------------------------------------------------------
-# | Document modes                                                     |
-# ----------------------------------------------------------------------
-
-# Force Internet Explorer 8/9/10 to render pages in the highest mode
-# available in various cases when it may not.
-#
-# https://hsivonen.fi/doctype/#ie8
-#
-# (!) Starting with Internet Explorer 11, document modes are deprecated.
-#     If your business still relies on older web apps and services that were
-#     designed for older versions of Internet Explorer, you might want to
-#     consider enabling `Enterprise Mode` throughout your company.
-#
-# https://msdn.microsoft.com/en-us/library/ie/bg182625.aspx#docmode
-# https://blogs.msdn.microsoft.com/ie/2014/04/02/stay-up-to-date-with-enterprise-mode-for-internet-explorer-11/
-# https://msdn.microsoft.com/en-us/library/ff955275.aspx
-
-add_header X-UA-Compatible $x_ua_compatible;

nginx.conf

@@ -121,12 +121,6 @@ http {
     ~*text/(css|html|javascript)|application\/pdf|xml "strict-origin-when-cross-origin";
   }
 
-  # Add X-UA-Compatible for HTML documents.
-  # h5bp/internet_explorer/x-ua-compatible.conf
-  map $sent_http_content_type $x_ua_compatible {
-    ~*text/html "IE=edge";
-  }
-
   # Add Access-Control-Allow-Origin.
   # h5bp/cross-origin/requests.conf
   map $sent_http_content_type $cors {