adds help text for population field on admin budgets groups

app/views/admin/budgets/_group.html.erb

@@ -49,12 +49,16 @@
           <div class="row">
             <div class="small-12 medium-6 column">
               <label><%= t("admin.budgets.form.population") %></label>
+              <p class="help-text" id="budgets-population-help-text">
+                <%= t("admin.budgets.form.population_help_text") %>
+              </p>
               <%= f.number_field :population,
                                 label: false,
                                 maxlength: 8,
                                 min: 1,
                                 placeholder: t("admin.budgets.form.population"),
-                                data: {toggle_focus: "population-info"} %>
+                                data: {toggle_focus: "population-info"},
+                                aria: {describedby: "budgets-population-help-text"} %>
             </div>
             <div class="small-12 medium-6 column " >
               <div id="population-info" class="is-hidden" data-toggler="is-hidden">

config/locales/en/admin.yml

@@ -102,7 +102,8 @@ en:
         heading: Heading name
         add_heading: Add heading
         amount: Amount
-        population: Population
+        population: "Population (optional)"
+        population_help_text: "This data is used exclusively to calculate the participation statistics"
         save_heading: Save heading
         no_heading: This group has no assigned heading.
         table_heading: Heading

config/locales/es/admin.yml

@@ -103,7 +103,8 @@ es:
         heading: Nombre de la partida
         add_heading: Añadir partida
         amount: Cantidad
-        population: Población
+        population: "Población (opcional)"
+        population_help_text: "Este dato se utiliza exclusivamente para calcular las estadísticas de participación"
         save_heading: Guardar partida
         no_heading: Este grupo no tiene ninguna partida asignada.
         table_heading: Partida