Fix indent in String#casecmp comments

mrbgems/mruby-string-ext/mrblib/string.rb

@@ -36,16 +36,17 @@ class String
     (s == self) ? nil : self.replace(s)
   end
 
-# call-seq:
-#    str.casecmp(other_str)   -> -1, 0, +1 or nil
-#
-# Case-insensitive version of <code>String#<=></code>.
-#
-#    "abcdef".casecmp("abcde")     #=> 1
-#    "aBcDeF".casecmp("abcdef")    #=> 0
-#    "abcdef".casecmp("abcdefg")   #=> -1
-#    "abcdef".casecmp("ABCDEF")    #=> 0
-#
+  ##
+  # call-seq:
+  #    str.casecmp(other_str)   -> -1, 0, +1 or nil
+  #
+  # Case-insensitive version of <code>String#<=></code>.
+  #
+  #    "abcdef".casecmp("abcde")     #=> 1
+  #    "aBcDeF".casecmp("abcdef")    #=> 0
+  #    "abcdef".casecmp("abcdefg")   #=> -1
+  #    "abcdef".casecmp("ABCDEF")    #=> 0
+  #
   def casecmp(str)
     self.downcase <=> str.to_str.downcase
   rescue NoMethodError