[ci skip] Remove style of the word Rails at the top

Similarly to https://github.com/rails/rails/pull/32626/commits/9c3fe52f5fa9904b43bf76be13f85db57c223d0c

README.md

@@ -2,7 +2,7 @@
 
 ## What's Rails
 
-**Rails** is a web-application framework that includes everything needed to
+Rails is a web-application framework that includes everything needed to
 create database-backed web applications according to the
 [Model-View-Controller (MVC)](http://en.wikipedia.org/wiki/Model-view-controller)
 pattern.