Add Goldmark as the new default markdown handler

This commit adds the fast and CommonMark compliant Goldmark as the new default markdown handler in Hugo.

If you want to continue using BlackFriday as the default for md/markdown extensions, you can use this configuration:

```toml
[markup]
defaultMarkdownHandler="blackfriday"
```

Fixes #5963
Fixes #1778
Fixes #6355

1 files changed, 161 insertions, 6 deletions

diff --git a/docs/data/docs.json b/docs/data/docs.json
index 1c09a788e..0944ab881 100644
--- a/docs/data/docs.json
+++ b/docs/data/docs.json
@@ -2,6 +2,13 @@
   "chroma": {
     "lexers": [
       {
+        "Name": "ABAP",
+        "Aliases": [
+          "ABAP",
+          "abap"
+        ]
+      },
+      {
         "Name": "ABNF",
         "Aliases": [
           "abnf"
@@ -135,6 +142,13 @@
         ]
       },
       {
+        "Name": "BibTeX",
+        "Aliases": [
+          "bib",
+          "bibtex"
+        ]
+      },
+      {
         "Name": "BlitzBasic",
         "Aliases": [
           "b3d",
@@ -405,7 +419,8 @@
         "Aliases": [
           "forth",
           "frt",
-          "fs"
+          "fs",
+          "fth"
         ]
       },
       {
@@ -580,12 +595,27 @@
         ]
       },
       {
+        "Name": "Igor",
+        "Aliases": [
+          "igor",
+          "igorpro",
+          "ipf"
+        ]
+      },
+      {
         "Name": "Io",
         "Aliases": [
           "io"
         ]
       },
       {
+        "Name": "J",
+        "Aliases": [
+          "ijs",
+          "j"
+        ]
+      },
+      {
         "Name": "JSON",
         "Aliases": [
           "json"
@@ -1342,6 +1372,63 @@
       }
     ]
   },
+  "config": {
+    "markup": {
+      "defaultMarkdownHandler": "goldmark",
+      "highlight": {
+        "style": "monokai",
+        "codeFences": true,
+        "noClasses": true,
+        "lineNos": false,
+        "lineNumbersInTable": true,
+        "lineNoStart": 1,
+        "hl_Lines": "",
+        "tabWidth": 4
+      },
+      "tableOfContents": {
+        "startLevel": 2,
+        "endLevel": 3
+      },
+      "goldmark": {
+        "renderer": {
+          "hardWraps": false,
+          "xHTML": false,
+          "unsafe": false
+        },
+        "parser": {
+          "autoHeadingID": true,
+          "attribute": true
+        },
+        "extensions": {
+          "typographer": true,
+          "footnote": true,
+          "definitionList": true,
+          "table": true,
+          "strikethrough": true,
+          "linkify": true,
+          "taskList": true
+        }
+      },
+      "blackFriday": {
+        "smartypants": true,
+        "smartypantsQuotesNBSP": false,
+        "angledQuotes": false,
+        "fractions": true,
+        "hrefTargetBlank": false,
+        "nofollowLinks": false,
+        "noreferrerLinks": false,
+        "smartDashes": true,
+        "latexDashes": true,
+        "taskLists": true,
+        "plainIDAnchors": true,
+        "extensions": null,
+        "extensionsMask": null,
+        "skipHTML": false,
+        "footnoteAnchorPrefix": "",
+        "footnoteReturnLinkContents": ""
+      }
+    }
+  },
   "media": {
     "types": [
       {
@@ -1513,6 +1600,68 @@
         "suffixes": [
           "scss"
         ]
+      },
+      {
+        "type": "video/3gpp",
+        "string": "video/3gpp",
+        "mainType": "video",
+        "subType": "3gpp",
+        "delimiter": ".",
+        "suffixes": [
+          "3gpp",
+          "3gp"
+        ]
+      },
+      {
+        "type": "video/mp4",
+        "string": "video/mp4",
+        "mainType": "video",
+        "subType": "mp4",
+        "delimiter": ".",
+        "suffixes": [
+          "mp4"
+        ]
+      },
+      {
+        "type": "video/mpeg",
+        "string": "video/mpeg",
+        "mainType": "video",
+        "subType": "mpeg",
+        "delimiter": ".",
+        "suffixes": [
+          "mpg",
+          "mpeg"
+        ]
+      },
+      {
+        "type": "video/ogg",
+        "string": "video/ogg",
+        "mainType": "video",
+        "subType": "ogg",
+        "delimiter": ".",
+        "suffixes": [
+          "ogv"
+        ]
+      },
+      {
+        "type": "video/webm",
+        "string": "video/webm",
+        "mainType": "video",
+        "subType": "webm",
+        "delimiter": ".",
+        "suffixes": [
+          "webm"
+        ]
+      },
+      {
+        "type": "video/x-msvideo",
+        "string": "video/x-msvideo",
+        "mainType": "video",
+        "subType": "x-msvideo",
+        "delimiter": ".",
+        "suffixes": [
+          "avi"
+        ]
       }
     ]
   },
@@ -2290,10 +2439,10 @@
           ]
         },
         "Eq": {
-          "Description": "Eq returns the boolean truth of arg1 == arg2.",
+          "Description": "Eq returns the boolean truth of arg1 == arg2 || arg1 == arg3 || arg1 == arg4.",
           "Args": [
-            "x",
-            "y"
+            "first",
+            "others"
           ],
           "Aliases": [
             "eq"
@@ -2454,7 +2603,7 @@
           ]
         },
         "Dictionary": {
-          "Description": "Dictionary creates a map[string]interface{} from the given parameters by\nwalking the parameters and treating them as key-value pairs.  The number\nof parameters must be even.",
+          "Description": "Dictionary creates a map[string]interface{} from the given parameters by\nwalking the parameters and treating them as key-value pairs.  The number\nof parameters must be even.\nThe keys can be string slices, which will create the needed nested structure.",
           "Args": [
             "values"
           ],
@@ -2521,7 +2670,7 @@
           "Description": "Index returns the result of indexing its first argument by the following\narguments. Thus \"index x 1 2 3\" is, in Go syntax, x[1][2][3]. Each\nindexed item must be a map, slice, or array.\n\nCopied from Go stdlib src/text/template/funcs.go.\n\nWe deviate from the stdlib due to https://github.com/golang/go/issues/14751.\n\nTODO(moorereason): merge upstream changes.",
           "Args": [
             "item",
-            "indices"
+            "args"
           ],
           "Aliases": [
             "index"
@@ -2630,6 +2779,12 @@
             ]
           ]
         },
+        "Reverse": {
+          "Description": "",
+          "Args": null,
+          "Aliases": null,
+          "Examples": null
+        },
         "Seq": {
           "Description": "Seq creates a sequence of integers.  It's named and used as GNU's seq.\n\nExamples:\n    3 =\u003e 1, 2, 3\n    1 2 4 =\u003e 1, 3\n    -3 =\u003e -1, -2, -3\n    1 4 =\u003e 1, 2, 3, 4\n    1 -2 =\u003e 1, 0, -1, -2",
           "Args": [