Update Gnuplot documentation (5.4.0)

lib/docs/filters/gnuplot/clean_html.rb

@@ -1,3 +1,4 @@
+# coding: utf-8
 module Docs
   class Gnuplot
     class CleanHtmlFilter < Filter
@@ -14,6 +15,9 @@ module Docs
           title = css('.HUGE')[0]
           title.name = 'h1'
 
+          # weird .svg links
+          css('#tex2html_wrap21553').remove
+
           subtitle = css('.XLARGE')[0]
           title.content = title.content + ' − ' + subtitle.content
 

lib/docs/scrapers/gnuplot.rb

@@ -1,7 +1,7 @@
 module Docs
   class Gnuplot < FileScraper
     self.type = 'gnuplot'
-    self.release = '5.2.8'
+    self.release = '5.4.0'
     self.links = {
       home: 'http://www.gnuplot.info/',
       code: 'https://sourceforge.net/projects/gnuplot/'