Optimize meta descriptions and more

bootstrap.md

@@ -3,6 +3,8 @@ title: Bootstrap
 layout: 2017/sheet
 prism_languages: [scss, haml, html]
 weight: -1
+description: |
+  .container .row .col-md-6, @screen-sm-min, .form-control, grids, .modal-content, tooltips, and other Bootstrap CSS examples.
 ---
 
 ### Screen sizes

chai.md

@@ -5,6 +5,8 @@ layout: 2017/sheet
 weight: -3
 updated: 2017-08-30
 version: chai v4.x
+description: |
+  expect(x).to.be.equal(y) 〉 assert.equal(x, y) 〉 .to.be.true 〉 jQuery, assertions, TDD and BDD, and other Chai examples.
 ---
 
 ### Assert

httpie.md

@@ -4,6 +4,8 @@ category: CLI
 layout: 2017/sheet
 weight: -3
 updated: 2017-09-04
+description: |
+  $ http POST http://example.com name="John" Host:example.com — JSON, cookies, files, auth, and other httpie examples.
 intro: |
   [HTTPie](https://httpie.org/) is a command-line HTTP client.
 ---

xpath.md

@@ -4,6 +4,8 @@ category: HTML
 layout: 2017/sheet
 tags: [Featured]
 weight: -5
+description: |
+  $x('//div//p//*') == $('div p *'), $x('//[@id="item"]') == $('#item'), and many other Xpath examples.
 ---
 
 ## Testing