Merge branch 'fix-slides-week-2' into 'UACCESS-23fa'

Adding Contrast Checker link

See merge request undergrad-accessibility-website!27

slides/presenting-accessibly.html

@@ -154,7 +154,7 @@ Can a BVI person follow your presentation and get the same information as someon
 - Image descriptions
 - Use headers & styles
 - Color contrast
-  - We'll talk about this more, but you can use [this tool](TBD) to make sure that people with color blindness or other color-related accessibility needs can read your slides
+  - We'll talk about this more, but you can use [this tool](https://webaim.org/resources/contrastchecker/) to make sure that people with color blindness or other color-related accessibility needs can read your slides
 
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 # Slideshow Basics (4/9)