docs(theming) fix typo in code example comment (#15127)

Gi11i4m · jelbourn · commit d41004411d2b · 2019-02-11T15:49:35.000-08:00
diff --git a/guides/theming-your-components.md b/guides/theming-your-components.md
@@ -93,7 +93,7 @@ For example:
   // Get a relative color for a hue ('lighter' or 'darker')
   outline-color: mat-color($accent, lighter);
 
-  // Get a constrast color for a hue by adding `-contrast` to any other key.
+  // Get a contrast color for a hue by adding `-contrast` to any other key.
   border-color: mat-color($primary, '100-contrast');
 }
 ```

Original file line number	Diff line number	Diff line change
`@@ -93,7 +93,7 @@ For example:`
`93`	`93`	`// Get a relative color for a hue ('lighter' or 'darker')`
`94`	`94`	`outline-color: mat-color($accent, lighter);`
`95`	`95`
`96`		- // Get a constrast color for a hue by adding `-contrast` to any other key.
	`96`	+ // Get a contrast color for a hue by adding `-contrast` to any other key.
`97`	`97`	`border-color: mat-color($primary, '100-contrast');`
`98`	`98`	`}`
`99`	`99`	```