Merge pull request #977 from danchristian/patch-1

docs: fix link URLs in  spacing.md

Author: shawnbot

docs/content/support/spacing.md

@@ -22,9 +22,9 @@ The spacing scale is a **base-8** scale. We chose a base-8 scale because eight i
 | `$spacer-5` | 5     | 32px  |
 | `$spacer-6` | 6     | 40px  |
 
-These variables are encouraged to be used within components and custom CSS. The spacing scale is also used for [margin](/css/utilities/margin) and [padding](/css/utilities/padding) utilities.
+These variables are encouraged to be used within components and custom CSS. The spacing scale is also used for [margin](/utilities/margin) and [padding](/utilities/padding) utilities.
 
-See [primer-marketing-support](/css/support/marketing-variables) for the extended spacing scale used for marketing needs and the related y-axis spacing utilities for [margin](/css/utilities/marketing-margin) and [padding](/css/utilities/marketing-padding).
+See [primer-marketing-support](/support/marketing-variables) for the extended spacing scale used for marketing needs and the related y-axis spacing utilities for [margin](/utilities/marketing-margin) and [padding](/utilities/marketing-padding).
 
 ## Em-based spacing
 
@@ -41,4 +41,4 @@ We aim for whole numbers, however, GitHub's body font-size is 14px which is diff
 | `$em-spacer-5` | 1/2      | .5             | 35                               | 40                   |
 | `$em-spacer-6` | 3/4      | .75            | 42                               | 48                   |
 
-The variables listed above are preferred for use within components and custom CSS. To calculate values with other font-sizes or em values, we suggest using [Formula](http://jxnblk.com/formula/).
+The variables listed above are preferred for use within components and custom CSS. To calculate values with other font-sizes or em values, we suggest using [Formula](http://jxnblk.com/formula).

docs/content/utilities/flexbox.md

@@ -15,7 +15,7 @@ Flex utilities can be used to apply `flexbox` behaviors to elements by using uti
 
 Before using these utilities, **you should be familiar with CSS3 Flexible Box spec**. If you are not, check out MDN's guide:
 
-:book: **[Using CSS Flexible Boxes](https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Flexible_Box_Layout/Using_CSS_flexible_boxes)**
+📖 **[Using CSS Flexible Boxes](https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Flexible_Box_Layout/Using_CSS_flexible_boxes)**
 
 ## Flex container