update mrblib/*.rb files to conform (some of) Rubocop checks

mrblib/array.rb

@@ -34,7 +34,7 @@ class Array
     return to_enum :each_index unless block_given?
 
     idx = 0
-    while(idx < length)
+    while idx < length
       block.call(idx)
       idx += 1
     end
@@ -75,7 +75,7 @@ class Array
       self[size - 1] = nil  # allocate
 
       idx = 0
-      while(idx < size)
+      while idx < size
         self[idx] = (block)? block.call(idx): obj
         idx += 1
       end

mrblib/hash.rb

@@ -10,7 +10,7 @@ class Hash
   #  hash.
   #
   # ISO 15.2.13.4.1
-  def == (hash)
+  def ==(hash)
     return true if self.equal?(hash)
     begin
       hash = hash.to_hash
@@ -54,7 +54,7 @@ class Hash
   #
   # ISO 15.2.13.4.8
   def delete(key, &block)
-    if block && ! self.has_key?(key)
+    if block && !self.has_key?(key)
       block.call(key)
     else
       self.__delete(key)

mrblib/kernel.rb

@@ -27,7 +27,7 @@ module Kernel
   def loop(&block)
     return to_enum :loop unless block
 
-    while(true)
+    while true
       yield
     end
   rescue StopIteration

mrblib/numeric.rb

@@ -48,7 +48,7 @@ module Integral
     return to_enum(:downto, num) unless block_given?
 
     i = self.to_i
-    while(i >= num)
+    while i >= num
       block.call(i)
       i -= 1
     end
@@ -89,7 +89,7 @@ module Integral
     return to_enum(:upto, num) unless block_given?
 
     i = self.to_i
-    while(i <= num)
+    while i <= num
       block.call(i)
       i += 1
     end
@@ -106,12 +106,12 @@ module Integral
 
     i = if num.kind_of? Float then self.to_f else self end
     if step > 0
-      while(i <= num)
+      while i <= num
         block.call(i)
         i += step
       end
     else
-      while(i >= num)
+      while i >= num
         block.call(i)
         i += step
       end

mrblib/range.rb

@@ -32,7 +32,7 @@ class Range
 
     return self if (val <=> last) > 0
 
-    while((val <=> last) < 0)
+    while (val <=> last) < 0
       block.call(val)
       val = val.succ
     end

mrblib/string.rb

@@ -12,7 +12,7 @@ class String
   def each_line(&block)
     # expect that str.index accepts an Integer for 1st argument as a byte data
     offset = 0
-    while(pos = self.index(0x0a, offset))
+    while pos = self.index(0x0a, offset)
       block.call(self[offset, pos + 1 - offset])
       offset = pos + 1
     end
@@ -106,7 +106,7 @@ class String
   # +self+.
   def each_char(&block)
     pos = 0
-    while(pos < self.size)
+    while pos < self.size
       block.call(self[pos])
       pos += 1
     end
@@ -118,7 +118,7 @@ class String
   def each_byte(&block)
     bytes = self.bytes
     pos = 0
-    while(pos < bytes.size)
+    while pos < bytes.size
       block.call(bytes[pos])
       pos += 1
     end