docs(nav): nest table-calc pages under a Table calculations group

Removes the IA weirdness where "Table calculations" (overview) and
"Formula table calculations" (Beta guide) were peer entries. Now they
live inside a single "Table calculations" group, alongside the existing
"Table calculation functions" and "SQL templates" sub-groups (latter
renamed from "Table calc SQL templates" — cleaner given the parent
group already names the topic).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: joaoviana

docs.json

@@ -96,27 +96,32 @@
                   "guides/how-to-promote-content",
                   "guides/verified-content",
                   "guides/keyboard-shortcuts",
-                  "guides/table-calculations",
-                  "guides/formula-table-calculations",
                   {
-                    "group": "Table calculation functions",
+                    "group": "Table calculations",
                     "pages": [
-                      "references/table-calculation-functions/row-functions",
-                      "references/table-calculation-functions/pivot-functions",
-                      "references/table-calculation-functions/aggregate-functions"
-                    ]
-                  },
-                  {
-                    "group": "Table calc SQL templates",
-                    "pages": [
-                      "guides/table-calculations/sql-templates",
-                      "guides/table-calculations/table-calculation-sql-templates/percent-change-from-previous",
-                      "guides/table-calculations/table-calculation-sql-templates/percent-of-previous-value",
-                      "guides/table-calculations/table-calculation-sql-templates/percent-of-total-column",
-                      "guides/table-calculations/table-calculation-sql-templates/percent-of-group-pivot-total",
-                      "guides/table-calculations/table-calculation-sql-templates/rank-in-column",
-                      "guides/table-calculations/table-calculation-sql-templates/running-total",
-                      "guides/table-calculations/table-calculation-sql-templates/rolling-window"
+                      "guides/table-calculations",
+                      "guides/formula-table-calculations",
+                      {
+                        "group": "Table calculation functions",
+                        "pages": [
+                          "references/table-calculation-functions/row-functions",
+                          "references/table-calculation-functions/pivot-functions",
+                          "references/table-calculation-functions/aggregate-functions"
+                        ]
+                      },
+                      {
+                        "group": "SQL templates",
+                        "pages": [
+                          "guides/table-calculations/sql-templates",
+                          "guides/table-calculations/table-calculation-sql-templates/percent-change-from-previous",
+                          "guides/table-calculations/table-calculation-sql-templates/percent-of-previous-value",
+                          "guides/table-calculations/table-calculation-sql-templates/percent-of-total-column",
+                          "guides/table-calculations/table-calculation-sql-templates/percent-of-group-pivot-total",
+                          "guides/table-calculations/table-calculation-sql-templates/rank-in-column",
+                          "guides/table-calculations/table-calculation-sql-templates/running-total",
+                          "guides/table-calculations/table-calculation-sql-templates/rolling-window"
+                        ]
+                      }
                     ]
                   }
                 ]