more fixes syntax misstake

Author: hsbt

en/news/_posts/2015-12-11-ruby-2-3-0-preview2-released.md

@@ -34,9 +34,9 @@ debugging.
 [RubyVM::InstructionSequence#to_binary and .load_from_binary](https://bugs.ruby-lang.org/issues/11788) are introduced as experimental feature. With these features, we can make a ISeq (bytecode) pre-compilation system.
 
 Ruby 2.3 includes many performance tuning fixes.
-For example, [optimize Proc#call] (https://bugs.ruby-lang.org/issues/11569),
-[reconsider method entry data structure] (https://bugs.ruby-lang.org/issues/11278),
-[introducing new table data structure] (https://bugs.ruby-lang.org/issues/11420),
+For example, [optimize Proc#call](https://bugs.ruby-lang.org/issues/11569),
+[reconsider method entry data structure](https://bugs.ruby-lang.org/issues/11278),
+[introducing new table data structure](https://bugs.ruby-lang.org/issues/11420),
 machine code level tuning for object allocation and method calling code,
 and other many optimizations.