Merge pull request #3838 from xgqt/master

social-media-preview_pl_PL.png: add Polish translation

_translations/index_pl.md

@@ -1,8 +1,8 @@
 ---
 layout: signed
-title: An open letter in support of Richard M. Stallman
-description: An open letter in support of Richard Matthew Stallman being reinstated by the Free Software Foundation
-image: /assets/social-media-preview.png
+title: List otwarty wspierający Richarda M. Stallmana
+description: List otwarty wspierający Richarda Matthew Stallmana w powrocie do Fundacji Wolnego Oprogramowania
+image: /assets/social-media-preview_pl_PL.png
 locale: pl_PL
 twitter:
   card: summary_large_image