Correct typo in doc

Author: armano2

docs/rules/curly-bracket-spacing.md

@@ -24,7 +24,7 @@ This rule aims to enforce unified spacing of curly brackets.
 
 ## :wrench: Options
 
-Default casing is set to `always`
+Default spacing is set to `always`
 
 ```
 'vue/curly-bracket-spacing': [2, 'always'|'never']