content: Restructure using the Diátaxis model

Closes gohugoio#1289
Closes gohugoio#1573
Closes gohugoio#2308
Closes gohugoio#2355
Closes gohugoio#2448
Closes gohugoio#2461
Closes gohugoio#2850
Closes gohugoio#3172
Closes gohugoio#3187

Author: jmooring

.cspell.json

@@ -31,17 +31,17 @@
     "# cspell: ignore words joined with dot",
     "\\w+\\.\\w+",
     "# cspell: ignore strings within backticks",
-    "`.+`",
+    "`.+?`",
     "# cspell: ignore strings within double quotes",
-    "\".+\"",
+    "\".+?\"",
     "# cspell: ignore strings within brackets",
-    "\\[.+\\]",
+    "\\[.+?\\]",
     "# cspell: ignore strings within parentheses",
-    "\\(.+\\)",
+    "\\(.+?\\)",
     "# cspell: ignore words that begin with a slash",
     "/\\w+",
     "# cspell: ignore everything within action delimiters",
-    "\\{\\{.+\\}\\}",
+    "\\{\\{.+?\\}\\}",
     "# cspell: ignore everything after a right arrow",
     "\\s+→\\s+.+"
   ],
@@ -97,6 +97,7 @@
     "shortcode",
     "stringifier",
     "struct",
+    "structs",
     "toclevels",
     "unmarshal",
     "unpublishdate",
@@ -132,6 +133,7 @@
     "# ----------------------------------------------------------------------",
     "# cspell: ignore names",
     "# ----------------------------------------------------------------------",
+    "Ananke",
     "Atishay",
     "Cosette",
     "Eliott",
@@ -166,6 +168,7 @@
     "kubuntu",
     "lubuntu",
     "mathjax",
+    "mhchem",
     "nosql",
     "pandoc",
     "pkgin",
@@ -178,6 +181,7 @@
     "ccpa",
     "cpra",
     "ddmaurier",
+    "diátaxis",
     "dring",
     "fleqn",
     "inor",