Rename `ActionView::Base#run` to `#_run`

There was a recent change by @tenderlove to Action view which introduced
`ActionView::Base#run` [1].

We ran into an issue with our application because one of the core
concepts in our domain model is a `Run` which is exposed in most of our
views as a helper method, which now conflicts with this new method.

Although this is a public method it is not really meant to be part of
the public API.

In order to discourage public use of this method and to reduce the
chances of this method conflicting with helper methods we can prefix
this method with an underscore, renaming this method to `_run`.

[1] https://github.com/rails/rails/commit/c740ebdaf5

actionview/lib/action_view/base.rb

@@ -267,7 +267,7 @@ def initialize(lookup_context = nil, assigns = {}, controller = nil, formats = N
       _prepare_context
     end
 
-    def run(method, template, locals, buffer, &block)
+    def _run(method, template, locals, buffer, &block)
       _old_output_buffer, _old_virtual_path, _old_template = @output_buffer, @virtual_path, @current_template
       @current_template = template
       @output_buffer = buffer

actionview/lib/action_view/template.rb

@@ -173,7 +173,7 @@ def supports_streaming?
     def render(view, locals, buffer = ActionView::OutputBuffer.new, &block)
       instrument_render_template do
         compile!(view)
-        view.run(method_name, self, locals, buffer, &block)
+        view._run(method_name, self, locals, buffer, &block)
       end
     rescue => e
       handle_render_error(view, e)

actionview/lib/action_view/template/handlers/erb/erubi.rb

@@ -27,7 +27,7 @@ def evaluate(action_view_erb_handler_context)
               include action_view_erb_handler_context._routes.url_helpers
               class_eval("define_method(:_template) { |local_assigns, output_buffer| #{src} }", @filename || "(erubi)", 0)
             }.empty
-            view.run(:_template, nil, {}, ActionView::OutputBuffer.new)
+            view._run(:_template, nil, {}, ActionView::OutputBuffer.new)
           end
 
         private