Add setting to enable/disable hyperlink auditing.

See #612.

CHANGELOG.asciidoc

@@ -26,6 +26,7 @@ Added
 - New setting `ui -> smooth-scrolling`.
 - New setting `content -> webgl` to enable/disable https://www.khronos.org/webgl/[WebGL].
 - New setting `content -> css-regions` to enable/disable support for http://dev.w3.org/csswg/css-regions/[CSS Regions].
+- New setting `content -> hyperlink-auditing` to enable/disable support for https://html.spec.whatwg.org/multipage/semantics.html#hyperlink-auditing[hyperlink auditing].
 
 Changed
 ~~~~~~~

doc/help/settings.asciidoc

@@ -137,6 +137,7 @@
 |<<content-allow-plugins,allow-plugins>>|Enables or disables plugins in Web pages.
 |<<content-webgl,webgl>>|Enables or disables WebGL.
 |<<content-css-regions,css-regions>>|Enable or disable support for CSS regions.
+|<<content-hyperlink-auditing,hyperlink-auditing>>|Enable or disable hyperlink auditing (<a ping>).
 |<<content-geolocation,geolocation>>|Allow websites to request geolocations.
 |<<content-notifications,notifications>>|Allow websites to show notifications.
 |<<content-javascript-can-open-windows,javascript-can-open-windows>>|Whether JavaScript programs can open new windows.
@@ -1174,6 +1175,17 @@ Valid values:
 
 Default: +pass:[true]+
 
+[[content-hyperlink-auditing]]
+=== hyperlink-auditing
+Enable or disable hyperlink auditing (<a ping>).
+
+Valid values:
+
+ * +true+
+ * +false+
+
+Default: +pass:[false]+
+
 [[content-geolocation]]
 === geolocation
 Allow websites to request geolocations.

qutebrowser/config/configdata.py

@@ -617,6 +617,10 @@ def data(readonly=False):
              SettingValue(typ.Bool(), 'true'),
              "Enable or disable support for CSS regions."),
 
+            ('hyperlink-auditing',
+             SettingValue(typ.Bool(), 'false'),
+             "Enable or disable hyperlink auditing (<a ping>)."),
+
             ('geolocation',
              SettingValue(typ.BoolAsk(), 'ask'),
              "Allow websites to request geolocations."),

qutebrowser/config/websettings.py

@@ -258,6 +258,8 @@ MAPPINGS = {
             Attribute(QWebSettings.WebGLEnabled),
         'css-regions':
             Attribute(QWebSettings.CSSRegionsEnabled),
+        'hyperlink-auditing':
+            Attribute(QWebSettings.HyperlinkAuditingEnabled),
         'local-content-can-access-remote-urls':
             Attribute(QWebSettings.LocalContentCanAccessRemoteUrls),
         'local-content-can-access-file-urls':