[API] Code generator: termvectors code cleanup

Author: picandocodigo

elasticsearch-api/utils/thor/templates/_method_setup.erb

@@ -24,7 +24,7 @@
 
 method = <%= @spec.http_method %>
 <%- if @spec.method_name == 'termvectors' %>
-  endpoint = arguments.delete(:endpoint) || '_termvectors'
+  arguments.delete(:endpoint)
 <%- end -%>
 path   = <%= @spec.http_path %>
 <%- if [email protected]? || needs_ignore_404?(@spec.endpoint_name) || needs_complex_ignore_404?(@spec.endpoint_name)-%>

elasticsearch-api/utils/thor/templates/method.erb

@@ -63,11 +63,11 @@ end
   alias_method :<%= @spec.method_name %>?, :<%= @spec.method_name %>
 <%- end -%>
 <%- if @spec.method_name == 'termvectors' %>
-
   # Deprecated: Use the plural version, {#termvectors}
   #
   def termvector(arguments={})
-    termvectors(arguments.merge endpoint: '_termvector')
+    warn "[DEPRECATION] `termvector` is deprecated. Please use the plural version, `termvectors` instead."
+    termvectors(arguments.merge(endpoint: '_termvector'))
   end
 <%- end -%>
 <%- @spec.namespace_depth.downto(1) do |i| -%>