Update no-deprecated-colors.md

Author: colebemis

docs/rules/no-deprecated-colors.md

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+# Disallow references to deprecated color variables
+
+
+[Theming](https://primer.style/react/theming) in Primer React is made possible by a theme object that defines your application's colors, spacing, fonts, and more. The color variables in Primer React's default theme object are pulled from [Primer Primitives](). When a color variable is deprecated in Primer Primitives, it's important to remove references to that color variable before the variable removed from the library.   
+
+## Rule details
+
+This rule disallows references to color variables that are deprecated in [Primer Primitives](https://github.com/primer/primitives).
+
+
+👎 Examples of **incorrect** code for this rule:
+
+```jsx
+/* eslint no-deprecated-colors: "error" */
+import {Box, themeGet} from '@primer/components'
+import styled from 'styled-components'
+
+const Example() = () => <Box color="some.deprecated.color">Incorrect</Box>
+
+const StyledExample = styled.div`
+  color: ${themeGet('some.deprecated.color')};
+`
+```
+
+👍 Examples of **correct** code for this rule:
+
+```jsx
+/* eslint no-deprecated-colors: "error" */
+import {Box, themeGet} from '@primer/components'
+import styled from 'styled-components'
+
+const Example() = () => <Box color="some.color">Correct</Box>
+
+const StyledExample = styled.div`
+  color: ${themeGet('some.color')};
+`
+```