Fix encoding of body in the email template

src/main/resources/messages.properties

@@ -47,12 +47,12 @@ AbstractUserDetailsAuthenticationProvider.credentialsExpired=User credentials ha
 
 # when a domain is not allowed, those are used to prefill the contact email
 # {0} contains the domain part
-LoginController.domainNotAllowedSubject=Attempting to register with {0} as an email domain is not allowed
+LoginController.domainNotAllowedSubject=Register with an email address from {0}
 # {0} contains the email address, {1} contains the domain part and {2} contains the user's full name
 LoginController.domainNotAllowedBody=Hello!\n\
   \n\
-  I am trying to register {0} and it appears that {1} is not in your allowed list of email domains. Could you please \
-  include it?\n\
+  I am trying to register with {0} and it appears that {1} is not an allowed email provider. Could you please include \
+  it?\n\
   \n\
   Best,\n\
   {2}

src/main/resources/templates/registration.html

@@ -14,8 +14,9 @@ <h4 class="form-signin-heading"><a th:href="@{/login}" th:text="#{rdp.site.fulln
         <h6 class="form-signin-subheading">Researcher Registry</h6>
         <div th:replace="layouts/login::message"></div>
         <div th:if="${domainNotAllowed}" class="alert alert-danger">
-            Yikes! It looks like your email does not belong to an allowed provider. If you think this is a mistake,
-            <a th:href="@{mailto:__${@siteSettings.contactEmail}__?from=__${domainNotAllowedFrom}__&subject=__${domainNotAllowedSubject}__&body=__${domainNotAllowedBody}__}">
+            Yikes! It looks like your email address was not issued from an allowed provider. If you think this is a
+            mistake,
+            <a th:href="@{mailto:__${@siteSettings.contactEmail}__(from=${domainNotAllowedFrom},subject=${domainNotAllowedSubject},body=${domainNotAllowedBody})}">
                 contact us
             </a>
             so that we can complete your registration.