translate(sidebar-home): add missing title translation for installation and describing-the-ui pages (#436)

Author: oxcened

src/sidebarHome.json

@@ -11,15 +11,15 @@
       "path": "/learn"
     },
     {
-      "title": "Installation",
+      "title": "Installazione",
       "path": "/learn/installation"
     },
     {
       "hasSectionHeader": true,
       "sectionHeader": "LEARN REACT"
     },
     {
-      "title": "Describing the UI",
+      "title": "Descrivere la UI",
       "path": "/learn/describing-the-ui"
     },
     {