build: Use prettier for markdown

Stop ignoring .md files in prettier and fix existing issues.

docs/i18n.md

@@ -7,11 +7,13 @@ The internationalization of the application is managed by [ngx-translate](https:
 ### In HTML templates
 
 Use the `translate` directive on an HTML element to automatically translate its content:
+
 ```html
 <span translate>This text will be translated.</span>
 ```
 
 You can also use the `translate` pipe if needed:
+
 ```html
 <button title="{{'Add item' | translate}}">+</button>
 ```
@@ -23,7 +25,9 @@ If you need to translate strings in JavaScript code, import the `TranslateServic
 
 ```typescript
 let title;
-translateService.get('My page title').subscribe((res: string) => { title = res; });
+translateService.get('My page title').subscribe((res: string) => {
+  title = res;
+});
 ```
 
 or `TranslateService` dependency and use the asynchronous
@@ -46,16 +50,16 @@ Do no forget to edit the files in `src/environment` to add the supported languag
 These are the Language available now:
 
 |  Language  | Code |    File    |
-|:----------:|:----:|:----------:|
-| Czech      |  cs  | cs-CS.json |
-| German     |  de  | de-DE.json |
-| English    |  en  | en-US.json |
-| Spanish    |  es  | es-MX.json |
-| French     |  fr  | fr-FR.json |
-| Italian    |  it  | it-IT.json |
-| Korean     |  ko  | ko-KO.json |
+| :--------: | :--: | :--------: |
+|   Czech    |  cs  | cs-CS.json |
+|   German   |  de  | de-DE.json |
+|  English   |  en  | en-US.json |
+|  Spanish   |  es  | es-MX.json |
+|   French   |  fr  | fr-FR.json |
+|  Italian   |  it  | it-IT.json |
+|   Korean   |  ko  | ko-KO.json |
 | Lithuanian |  li  | li-LI.json |
-| Latvian    |  lv  | lv-LV.json |
-| Nepali     |  ne  | ne-NE.json |
+|  Latvian   |  lv  | lv-LV.json |
+|   Nepali   |  ne  | ne-NE.json |
 | Portuguese |  pt  | pt-PT.json |
-| Swahili    |  sw  | sw-SW.json |
+|  Swahili   |  sw  | sw-SW.json |