Docs: fix an accidental replacement.

Author: mysticatea

docs/rules/no-missing-import.md

@@ -2,7 +2,7 @@
 
 This is similar to [no-missing-require](no-missing-require.md), but this rule handles `import` and `export` declarations.
 
-:warning: ECMAScript "error"015 (ES6) does not define the lookup logic and Node does not support modules yet. So this rule spec might be changed in future.
+:warning: ECMAScript 2015 (ES6) does not define the lookup logic and Node does not support modules yet. So this rule spec might be changed in future.
 
 ## Rule Details