Fixes for :library alias specs

Author: eregon

library/socket/socket/socketpair_spec.rb

@@ -1,7 +1,7 @@
 require_relative '../spec_helper'
 
 describe "Socket.socketpair" do
-  it "is an alias for Socket.pair" do
+  it "is an alias of Socket.pair" do
     Socket.method(:socketpair).should == Socket.method(:pair)
   end
 end

library/stringio/isatty_spec.rb

@@ -2,7 +2,7 @@
 require 'stringio'
 
 describe "StringIO#isatty" do
-  it "is an alias of StringIO.tty?" do
+  it "is an alias of StringIO#tty?" do
     StringIO.instance_method(:isatty).should == StringIO.instance_method(:tty?)
   end
 end

library/stringio/tell_spec.rb

@@ -2,7 +2,7 @@
 require 'stringio'
 
 describe "StringIO#tell" do
-  it "is an alias of StringIO.pos" do
+  it "is an alias of StringIO#pos" do
     StringIO.instance_method(:tell).should == StringIO.instance_method(:pos)
   end
 end

library/stringscanner/pointer_spec.rb

@@ -6,3 +6,9 @@
     StringScanner.instance_method(:pointer).should == StringScanner.instance_method(:pos)
   end
 end
+
+describe "StringScanner#pointer=" do
+  it "is an alias of StringScanner#pos=" do
+    StringScanner.instance_method(:pointer=).should == StringScanner.instance_method(:pos=)
+  end
+end