Add missing keyboard shortcuts to guide

shared/i18n/locales/en_US/translation.json

@@ -689,6 +689,7 @@
   "Toggle navigation": "Toggle navigation",
   "Focus search input": "Focus search input",
   "Open this guide": "Open this guide",
+  "Enter": "Enter",
   "Publish document and exit": "Publish document and exit",
   "Save document": "Save document",
   "Cancel editing": "Cancel editing",
@@ -701,10 +702,16 @@
   "Undo": "Undo",
   "Redo": "Redo",
   "Lists": "Lists",
+  "Tab": "Tab",
   "Indent list item": "Indent list item",
   "Outdent list item": "Outdent list item",
   "Move list item up": "Move list item up",
   "Move list item down": "Move list item down",
+  "Tables": "Tables",
+  "Insert row": "Insert row",
+  "Next cell": "Next cell",
+  "Previous cell": "Previous cell",
+  "Space": "Space",
   "Numbered list": "Numbered list",
   "Blockquote": "Blockquote",
   "Horizontal divider": "Horizontal divider",