Fix a11y resources document (#513)

* del:duplicates

* prettier

Author: yamanoku

src/guide/a11y-resources.md

@@ -24,18 +24,13 @@
 - Automated Tools
   - [Lighthouse](https://chrome.google.com/webstore/detail/lighthouse/blipmdconlkpinefehnmjammfjpmpbjk)
   - [WAVE](https://chrome.google.com/webstore/detail/wave-evaluation-tool/jbbplnpkjmmeebjpijfedlgcdilocofh)
-
 - Color Tools
   - [WebAim Color Contrast](https://webaim.org/resources/contrastchecker/)
   - [WebAim Link Color Contrast](https://webaim.org/resources/linkcontrastchecker)
-
 - Other Helpful Tools
   - [HeadingMap](https://chrome.google.com/webstore/detail/headingsmap/flbjommegcjonpdmenkdiocclhjacmbi?hl=en…)
-  
   - [Color Oracle](https://colororacle.org)
-  
   - [Focus Indicator](https://chrome.google.com/webstore/detail/focus-indicator/heeoeadndnhebmfebjccbhmccmaoedlf?hl=en-US…)
-  
   - [NerdeFocus](https://chrome.google.com/webstore/detail/nerdefocus/lpfiljldhgjecfepfljnbjnbjfhennpd?hl=en-US…)
 
 ## Users
@@ -45,11 +40,8 @@ The World Health Organization estimates that 15% of the world's population has s
 There are a huge range of disabilities, which can be divided roughly into four categories:
 
 - _[Visual](https://webaim.org/articles/visual/)_ - These users can benefit from the use of screen readers, screen magnification, controlling screen contrast, or braille display.
-
 - _[Auditory](https://webaim.org/articles/auditory/)_ - These users can benefit from captioning, transcripts or sign   language video.
-
-- _[Motor](https://webaim.org/articles/motor/)_ - These users can benefit from a range of [assistive technologies for motor impairments](https://webaim.org/articles/motor/assistive): voice recognition software, eye tracking, single-switch access, head wand, single-switch access, sip and puff switch, oversized trackball mouse, adaptive keyboard or other assistive technologies.
-
+- _[Motor](https://webaim.org/articles/motor/)_ - These users can benefit from a range of [assistive technologies for motor impairments](https://webaim.org/articles/motor/assistive): voice recognition software, eye tracking, single-switch access, head wand, sip and puff switch, oversized trackball mouse, adaptive keyboard or other assistive technologies.
 - _[Cognitive](https://webaim.org/articles/cognitive/)_ - These users can benefit from supplemental media, structural organization of content, clear and simple writing.
 
 Check out the following links from WebAim to understand from users: