Render bracket references as superscript text

This commit improves markdown rendering to convert reference labels
(e.g., `[1]`) to superscripts, improving document readability without
cluttering the text. This improvement applies documentation of all
scripts and categories.

Changes:

- Implement superscript conversion for reference labels within markdown
  content, ensuring a cleaner presentation of textual references.
- Enable HTML content within markdown, necessary for inserting `<sup>`
  elements due to limitations in `markdown-it`, see
  markdown-it/markdown-it#999 for details.
- Refactor markdown rendering process for improved testability and
  adherence to the Single Responsibility Principle.
- Create `_typography.scss` with font size definitions, facilitating
  better control over text presentation.
- Adjust external URL indicator icon sizing for consistency, aligning
  images with the top of the text to maintain a uniform appearence.
- Use normal font-size explicitly for documentation text to ensure
  consistency.
- Remove text size specification in `markdown-styles` mixin, using `1em`
  for spacing to simplify styling.
- Rename font sizing variables for clarity, distinguishing between
  absolute and relative units.
- Change `font-size-relative-smaller` to be `80%`, browser default for
  `font-size: smaller;` CSS style and use it with `<sup>` elements.
- Improve the logic for converting plain URLs to hyperlinks, removing
  trailing whitespace for cleaner link generation.
- Fix plain URL to hyperlink (autolinking) logic removing trailing
  whitespace from the original markdown content. This was revealed by
  tests after separating its logic.
- Increase test coverage with more tests.
- Add types for `markdown-it` through `@types/markdown-it` package for
  better editor support and maintainability.
- Simplify implementation of adding custom anchor attributes in
  `markdown-it` using latest documentation.

package-lock.json

@@ -6,11 +6,12 @@
   "packages": {
     "": {
       "name": "privacy.sexy",
-      "version": "0.12.9",
+      "version": "0.12.10",
       "hasInstallScript": true,
       "dependencies": {
         "@floating-ui/vue": "^1.0.2",
         "@juggle/resize-observer": "^3.4.0",
+        "@types/markdown-it": "^13.0.7",
         "ace-builds": "^1.30.0",
         "electron-log": "^5.0.1",
         "electron-progressbar": "^2.1.0",
@@ -3395,6 +3396,20 @@
         "@types/node": "*"
       }
     },
+    "node_modules/@types/linkify-it": {
+      "version": "3.0.5",
+      "resolved": "https://registry.npmjs.org/@types/linkify-it/-/linkify-it-3.0.5.tgz",
+      "integrity": "sha512-yg6E+u0/+Zjva+buc3EIb+29XEg4wltq7cSmd4Uc2EE/1nUVmxyzpX6gUXD0V8jIrG0r7YeOGVIbYRkxeooCtw=="
+    },
+    "node_modules/@types/markdown-it": {
+      "version": "13.0.7",
+      "resolved": "https://registry.npmjs.org/@types/markdown-it/-/markdown-it-13.0.7.tgz",
+      "integrity": "sha512-U/CBi2YUUcTHBt5tjO2r5QV/x0Po6nsYwQU4Y04fBS6vfoImaiZ6f8bi3CjTCxBPQSO1LMyUqkByzi8AidyxfA==",
+      "dependencies": {
+        "@types/linkify-it": "*",
+        "@types/mdurl": "*"
+      }
+    },
     "node_modules/@types/mdast": {
       "version": "3.0.12",
       "resolved": "https://registry.npmjs.org/@types/mdast/-/mdast-3.0.12.tgz",
@@ -3404,6 +3419,11 @@
         "@types/unist": "^2"
       }
     },
+    "node_modules/@types/mdurl": {
+      "version": "1.0.5",
+      "resolved": "https://registry.npmjs.org/@types/mdurl/-/mdurl-1.0.5.tgz",
+      "integrity": "sha512-6L6VymKTzYSrEf4Nev4Xa1LCHKrlTlYCBMTlQKFuddo1CvQcE52I0mwfOJayueUC7MJuXOeHTcIU683lzd0cUA=="
+    },
     "node_modules/@types/ms": {
       "version": "0.7.31",
       "resolved": "https://registry.npmjs.org/@types/ms/-/ms-0.7.31.tgz",
@@ -21964,6 +21984,20 @@
         "@types/node": "*"
       }
     },
+    "@types/linkify-it": {
+      "version": "3.0.5",
+      "resolved": "https://registry.npmjs.org/@types/linkify-it/-/linkify-it-3.0.5.tgz",
+      "integrity": "sha512-yg6E+u0/+Zjva+buc3EIb+29XEg4wltq7cSmd4Uc2EE/1nUVmxyzpX6gUXD0V8jIrG0r7YeOGVIbYRkxeooCtw=="
+    },
+    "@types/markdown-it": {
+      "version": "13.0.7",
+      "resolved": "https://registry.npmjs.org/@types/markdown-it/-/markdown-it-13.0.7.tgz",
+      "integrity": "sha512-U/CBi2YUUcTHBt5tjO2r5QV/x0Po6nsYwQU4Y04fBS6vfoImaiZ6f8bi3CjTCxBPQSO1LMyUqkByzi8AidyxfA==",
+      "requires": {
+        "@types/linkify-it": "*",
+        "@types/mdurl": "*"
+      }
+    },
     "@types/mdast": {
       "version": "3.0.12",
       "resolved": "https://registry.npmjs.org/@types/mdast/-/mdast-3.0.12.tgz",
@@ -21973,6 +22007,11 @@
         "@types/unist": "^2"
       }
     },
+    "@types/mdurl": {
+      "version": "1.0.5",
+      "resolved": "https://registry.npmjs.org/@types/mdurl/-/mdurl-1.0.5.tgz",
+      "integrity": "sha512-6L6VymKTzYSrEf4Nev4Xa1LCHKrlTlYCBMTlQKFuddo1CvQcE52I0mwfOJayueUC7MJuXOeHTcIU683lzd0cUA=="
+    },
     "@types/ms": {
       "version": "0.7.31",
       "resolved": "https://registry.npmjs.org/@types/ms/-/ms-0.7.31.tgz",