Fix missing pjax on Web Archive

[wherewhere]

PR Checklist

• The changes have been tested (for bug fixes / features).
• Docs in NexT website have been added / updated (for features).

PR Type

• Bugfix.
• Feature.
• Improvement.
• Code style update (e.g. formatting, linting).
• Refactoring (no changes to functionality and APIs).
• Documentation.
• Translation.
• Other... Please describe:

What is the current behavior?

Issue resolved:

On Web Archive the js script has processed by wombat which will bring it into a if statement, such as

var _____WB$wombat$assign$function_____ = function(name) {return (self._wb_wombat && self._wb_wombat.local_init && self._wb_wombat.local_init(name)) || self[name]; };
if (!self.__WB_pmw) { self.__WB_pmw = function(obj) { this.__WB_source = obj; return this; } }
{
  let window = _____WB$wombat$assign$function_____("window");
  let self = _____WB$wombat$assign$function_____("self");
  let document = _____WB$wombat$assign$function_____("document");
  let location = _____WB$wombat$assign$function_____("location");
  let top = _____WB$wombat$assign$function_____("top");
  let parent = _____WB$wombat$assign$function_____("parent");
  let frames = _____WB$wombat$assign$function_____("frames");
  let opener = _____WB$wombat$assign$function_____("opener");

  // Then the original script.
}

Which cause first class field will not contained in window object. So I add if (!window.pjax) window.pjax = pjax to add pjax to window manually.

[coveralls]

Pull Request Test Coverage Report for Build 12646622716

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 97.451%

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Totals
Change from base Build 12568915428:	0.0%
Covered Lines:	400
Relevant Lines:	405

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💛 - Coveralls