[IMP] website: Explain scope of language in keywords in seo

When there is a website with traduction (for exemple, Spanish and
French). In the Spanish website, at the SEO menu, you can add keywords
using any of the languages (Spanish or French), but these keywords are
only added to the Spanish website.

To avoid misunderstanding between the website language and the keyword
language a tooltip is added.

closes odoo/odoo#29683

addons/website/i18n/website.pot

@@ -3723,6 +3723,13 @@ msgstr ""
 msgid "The installation of an App is already in progress."
 msgstr ""
 
+#. module: website
+#. openerp-web
+#: code:addons/website/static/src/xml/website.seo.xml:93
+#, python-format
+msgid "The language of the keyword and related keywords."
+msgstr ""
+
 #. module: website
 #: model_terms:ir.ui.view,arch_db:website.403
 msgid "The page you were looking for could not be authorized."

addons/website/static/src/xml/website.seo.xml

@@ -90,7 +90,7 @@
         <div class="form-inline" role="form">
             <div class="input-group">
                 <input type="text" name="website_meta_keywords" id="website_meta_keywords" class="form-control" placeholder="Keyword" maxlength="30"/>
-                <span class="input-group-append">
+                <span title="The language of the keyword and related keywords." class="input-group-append">
                     <select name="seo_page_language" id="language-box" class="btn form-control"/>
                 </span>
                 <span class="input-group-append">