feat: implement table of contents

package-lock.json

@@ -9627,6 +9627,14 @@
         "micromatch": "^3.1.10"
       }
     },
+    "gatsby-plugin-anchor-links": {
+      "version": "1.1.1",
+      "resolved": "https://registry.npmjs.org/gatsby-plugin-anchor-links/-/gatsby-plugin-anchor-links-1.1.1.tgz",
+      "integrity": "sha512-mgSHUAEa7RRWD/lcmJVUWD9mIT14EIJvMPcxJ1W2Ev+rNuqBBpk1j4vDWy1uxas+qusi0vrtZ4HdU7mse12qDw==",
+      "requires": {
+        "scroll-to-element": "^2.0.3"
+      }
+    },
     "gatsby-plugin-layout": {
       "version": "1.3.1",
       "resolved": "https://registry.npmjs.org/gatsby-plugin-layout/-/gatsby-plugin-layout-1.3.1.tgz",
@@ -16734,6 +16742,14 @@
       "resolved": "https://registry.npmjs.org/querystringify/-/querystringify-2.1.1.tgz",
       "integrity": "sha512-w7fLxIRCRT7U8Qu53jQnJyPkYZIaR4n5151KMfcJlO/A9397Wxb1amJvROTK6TOnp7PfoAmg/qXiNHI+08jRfA=="
     },
+    "raf": {
+      "version": "3.4.1",
+      "resolved": "https://registry.npmjs.org/raf/-/raf-3.4.1.tgz",
+      "integrity": "sha512-Sq4CW4QhwOHE8ucn6J34MqtZCeWFP2aQSmrlroYgqAV1PjStIhJXxYuTgUIfkEk7zTLjmIjLmU5q+fbD1NnOJA==",
+      "requires": {
+        "performance-now": "^2.1.0"
+      }
+    },
     "ramda": {
       "version": "0.27.0",
       "resolved": "https://registry.npmjs.org/ramda/-/ramda-0.27.0.tgz",
@@ -18233,6 +18249,14 @@
         "invariant": "^2.2.4"
       }
     },
+    "scroll-to-element": {
+      "version": "2.0.3",
+      "resolved": "https://registry.npmjs.org/scroll-to-element/-/scroll-to-element-2.0.3.tgz",
+      "integrity": "sha512-5herPcm9jMfQgRwu94lH5mei+2YhipR4RQ2nAvnBxJb2tG+P7O0ctOKAaAZBXbBejnn+MImh3wrAUA5EcLnjEQ==",
+      "requires": {
+        "raf": "^3.4.0"
+      }
+    },
     "scuid": {
       "version": "1.1.0",
       "resolved": "https://registry.npmjs.org/scuid/-/scuid-1.1.0.tgz",