Apply @ixti's reviews

Closes #87

Author: JuanitoFatas

README.md

@@ -735,7 +735,7 @@ Comparison:
 
 ##### `Proc#call` and block arguments vs `yield`[code](code/proc-and-block/proc-call-vs-yield.rb)
 
-[In MRI Ruby, block arguments are converted to Procs, which incurs a heap allocation](https://www.omniref.com/ruby/2.2.0/symbols/Proc/yield?#annotation=4087638&line=711).
+In MRI Ruby, block arguments [are converted to Procs](https://www.omniref.com/ruby/2.2.0/symbols/Proc/yield?#annotation=4087638&line=711), which incurs a heap allocation.
 
 ```
 $ ruby -v code/proc-and-block/proc-call-vs-yield.rb

code/proc-and-block/proc-call-vs-yield.rb

@@ -1,14 +1,14 @@
 require 'benchmark/ips'
 
-def slow &block
+def slow(&block)
   block.call
 end
 
-def slow2 &block
+def slow2(&block)
   yield
 end
 
-def slow3 &block
+def slow3(&block)
 
 end