Correct capitalisation in tabset example code (elixir-lang#1877)

Author: DavidOliver

README.md

@@ -310,7 +310,7 @@ IO.puts "Hello, world!"
 ### Erlang
 
 ```erlang
-io:fwrite("hello, world!\n").
+io:fwrite("Hello, world!\n").
 ```
 
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