added support for markdown-it-abbr (#238)

this makes it possible to use abbreviations like these
```
*[HTML]: Hyper Text Markup Language
*[W3C]:  World Wide Web Consortium
The HTML specification
is maintained by the W3C.
```

Co-authored-by: Philip Molares <philip@mauricedoepke.de>

package.json

@@ -38,6 +38,7 @@
     "i18next-browser-languagedetector": "5.0.0",
     "i18next-http-backend": "1.0.15",
     "markdown-it": "11.0.0",
+    "markdown-it-abbr": "^1.0.4",
     "markdown-it-deflist": "^2.0.3",
     "markdown-it-emoji": "1.4.0",
     "markdown-it-ins": "^3.0.0",

src/components/editor/markdown-preview/markdown-preview.tsx

@@ -2,6 +2,7 @@ import MarkdownIt from 'markdown-it'
 import emoji from 'markdown-it-emoji'
 import markdownItRegex from 'markdown-it-regex'
 import taskList from 'markdown-it-task-lists'
+import abbreviation from 'markdown-it-abbr'
 import definitionList from 'markdown-it-deflist'
 import subscript from 'markdown-it-sub'
 import superscript from 'markdown-it-sup'
@@ -40,6 +41,7 @@ const MarkdownPreview: React.FC<MarkdownPreviewProps> = ({ content }) => {
     })
     md.use(taskList)
     md.use(emoji)
+    md.use(abbreviation)
     md.use(definitionList)
     md.use(subscript)
     md.use(superscript)

src/external-types/markdown-it-abbr/index.d.ts

@@ -0,0 +1,6 @@
+
+declare module 'markdown-it-abbr' {
+  import MarkdownIt from 'markdown-it/lib'
+  const markdownItAbbreviation: MarkdownIt.PluginSimple
+  export = markdownItAbbreviation
+}

yarn.lock

@@ -7270,6 +7270,11 @@ map-visit@^1.0.0:
   dependencies:
     object-visit "^1.0.0"
 
+markdown-it-abbr@^1.0.4:
+  version "1.0.4"
+  resolved "https://registry.yarnpkg.com/markdown-it-abbr/-/markdown-it-abbr-1.0.4.tgz#d66b5364521cbb3dd8aa59dadfba2fb6865c8fd8"
+  integrity sha1-1mtTZFIcuz3Yqlna37ovtoZcj9g=
+
 markdown-it-deflist@^2.0.3:
   version "2.0.3"
   resolved "https://registry.yarnpkg.com/markdown-it-deflist/-/markdown-it-deflist-2.0.3.tgz#5727db04184d3cb2bc6ee4a9641e3a1091d5fd6f"