Bump Liquid to 5.11.0 (#2012)

This commit reverts the Inline Snippets tag (#2001) and bumps
Liquid to 5.11. For now, the inclusion of Inline Snippets
in the latest Liquid release is being treated as a bug.

While #2001 does implement the scope contained in RFC#1916,
we need to take a step back to make sure we’re setting our
sights high enough with this feature, and that we’re truly
supporting theme developers in the ways they need.

If you have any feedback, please leave a comment on RFC#1916.

- Liquid Developer Tools

lib/liquid/variable.rb

@@ -74,14 +74,14 @@ module Liquid
       p.consume(:end_of_string)
     end
 
-    def rigid_parse(markup)
+    def strict2_parse(markup)
       @filters = []
       p = @parse_context.new_parser(markup)
 
       return if p.look(:end_of_string)
 
       @name = parse_context.safe_parse_expression(p)
-      @filters << rigid_parse_filter_expressions(p) while p.consume?(:pipe)
+      @filters << strict2_parse_filter_expressions(p) while p.consume?(:pipe)
       p.consume(:end_of_string)
     end
 
@@ -156,7 +156,7 @@ module Liquid
     # argument = (positional_argument | keyword_argument)
     # positional_argument = expression
     # keyword_argument = id ":" expression
-    def rigid_parse_filter_expressions(p)
+    def strict2_parse_filter_expressions(p)
       filtername = p.consume(:id)
       filter_args = []
       keyword_args = {}