Issue 1625 - Improve string descriptions, addressing comments on CrowdIn

_locales/en_US/messages.json

 {
   "add": {
     "description": "This is the label for the 'Add' buttons.",
     "message": "Add"
   },
   "add_domain_button": {
     "message": "Add domain"
   },
   "add_filter_button": {
     "message": "Add filter"
   },
   "add_filters_msg": {
     "message": "Add filter(s)?"
   },
   "add_your_own_filters": {
     "message": "Add your own filters"
   },
   "apply_changes": {
     "message": "Apply changes"
   },
   "block_element": {
-    "description": "Action in context menu and popup UI, to add a filter which blocks an element selected from the current page",
-    "message": "Block element"
+    "description": "Context menu item that adds a filter which blocks the selected element",
+    "message": "Block Element"
   },
   "cancel": {
     "description": "Cancel button label",
     "message": "Cancel"
   },
   "clickhide_instructions": {
     "description": "Instructions shown in popup UI before it disapears, when \"Block element\" action is executed",
     "message": "After closing this popup, click (or right-click) an element on the page."
   },
   "description_chrome": {
     "description": "Note: this cannot be longer than 132 characters",
     "message": "The free adblock tool for Chrome: Blocks annoying video ads on YouTube, Facebook ads, banners and much more."
   },
   "description_opera": {
     "message": "The free adblock tool for Opera: Blocks annoying video ads on YouTube, Facebook ads, banners and much more."
   },
   "description_safari": {
     "message": "The free adblock tool for Safari: Blocks annoying video ads on YouTube, Facebook ads, banners and much more."
   },
   "disabled_for_site":
   {
     "description": "Popup balloon label to disable blocking",
     "message": "<strong>Disabled</strong> on this site"
   },
   "disabled_for_these_domains": {
     "message": "Adblock Plus is disabled for the domains listed below. You can add a domain either via the Adblock Plus icon in the address bar or by typing the domain (not a URL) in the box and clicking the \"Add domain\" button."
   },
+  "easy_create_filter": {
+    "description": "Action in popup UI to add a filter which blocks an element selected from the current page",
+    "message": "Block element"
+  },
   "edit_filters_raw": {
     "message": "Edit filters as raw text"
   },
   "enable_only_the": {
     "message": "Enable only the filter lists you need. Too many can make your browser unresponsive."
   },
   "enabled_for_site": {
     "description": "Popup balloon label to enable blocking",
     "message": "<strong>Enabled</strong> on this site"
   },
@@ skipping 136 matching lines @@
   "line": {
     "message": "Line $number$",
     "description": "Prepended to error messages to indicate the line number (e.g. \"Line 42: Some error on this line\")",
     "placeholders": {
       "number": {
         "content": "$1"
       }
     }
   }
 }