add alt text to learn-to-code images

views/resources/learn-to-code.jade

@@ -13,7 +13,7 @@ block content
  .panel.panel-info
  .panel-heading.landing-panel-heading.text-center Get Connected
  .panel-body
- img.img-responsive.img-center(src="https://s3.amazonaws.com/freecodecamp/about-chatroom.jpg")
+ img.img-responsive.img-center(src="https://s3.amazonaws.com/freecodecamp/about-chatroom.jpg" alt="A screen shot from Free Code Camp's main chat room")
  h3
  .row
  .col-xs-9.text-right Campers doing challenges:
@@ -25,14 +25,14 @@ block content
  .panel.panel-info
  .panel-heading.landing-panel-heading.text-center Learn JavaScript
  .panel-body
- img.img-responsive.img-center(src="https://s3.amazonaws.com/freecodecamp/about-github.jpg")
+ img.img-responsive.img-center(src="https://s3.amazonaws.com/freecodecamp/about-github.jpg" alt="A screen shot of a GitHub commit graph showing a streak of 33 consecutive days of contributions")
  h3
  include ../partials/github
  .col-xs-12.col-sm-12.col-md-4
  .panel.panel-info
  .panel-heading.landing-panel-heading.text-center Help Nonprofits
  .panel-body
- img.img-responsive.img-center(src="https://s3.amazonaws.com/freecodecamp/about-trello.jpg")
+ img.img-responsive.img-center(src="https://s3.amazonaws.com/freecodecamp/about-trello.jpg" alt="a screen shot of Free Code Camp's nonprofit project Trello board showing several active projects")
  h3
  .row
  .col-xs-6.text-right Days since we launched: