studio - soft landing: changing 'sign into' to 'sign in to' copy

cms/templates/login.html

@@ -8,7 +8,7 @@
 <div class="wrapper-content wrapper">
   <section class="content">
     <header>
-      <h1 class="title title-1">Sign into edX Studio</h1>
+      <h1 class="title title-1">Sign In to edX Studio</h1>
       <a href="${reverse('signup')}" class="action action-signin">Don't have a Studio Account? Sign up!</a>
     </header>
 
@@ -16,7 +16,7 @@
       <form id="login_form" method="post" action="login_post">
         
         <fieldset>
-          <legend class="sr">Required Information to Sign into edX Studio</legend>
+          <legend class="sr">Required Information to Sign In to edX Studio</legend>
           
           <ol class="list-input">
             <li class="field text required" id="field-email">
@@ -33,7 +33,7 @@
         </fieldset>
 
         <div class="form-actions">
-          <button type="submit" id="submit" name="submit" class="action action-primary">Sign into edX Studio</button>
+          <button type="submit" id="submit" name="submit" class="action action-primary">Sign In to edX Studio</button>
         </div>
 
         <!-- no honor code for CMS, but need it because we're using the lms student object -->