doc add description to vue-essential rules

docs/rules/vue-essential/global-style.md

@@ -2,3 +2,10 @@
 
 Checks if the component is using global styles instead of `scoped` styles. &nbsp;&nbsp;<br />
 👉 https://vuejs.org/style-guide/rules-essential.html#use-component-scoped-styling
+
+## ❓ Why it's good to follow this rule?
+
+- **Maintainability** limiting the `css` for the actual component makes it easier to maintain and understand.
+- **Isolation** the component is isolated and has no unwanted effect on the other parts of the application.
+- **Reusability** the component can be reused in other parts of the application with exactly the same look and feel.
+

docs/rules/vue-essential/simple-prop.md

@@ -2,3 +2,7 @@
 
 Checks if the component is using simple props definitions. &nbsp;&nbsp;<br />
 👉 https://vuejs.org/style-guide/rules-essential.html#use-detailed-prop-definitions
+
+## ❓ Why it's good to follow this rule?
+
+- **Readability** the component is easier to understand in details.

docs/rules/vue-essential/single-name-component.md

@@ -2,3 +2,8 @@
 
 Checks if the component name is a single word. &nbsp;&nbsp;<br />
 👉 https://vuejs.org/style-guide/rules-essential.html#use-multi-word-component-names
+
+## ❓ Why it's good to follow this rule?
+
+- **Consistency** the component name is consistent with the other components.
+- **Readability** the component name is more descriptive about its goal.

docs/rules/vue-essential/vfor-no-key.md

@@ -3,3 +3,7 @@
 Checks if the component is using `v-for` without a `key` property. &nbsp;&nbsp;<br />
 👉 https://vuejs.org/style-guide/rules-essential.html#use-keyed-v-for
 
+## ❓ Why it's good to follow this rule?
+
+- **Performance** adding a `key` property to the `v-for` loop helps Vue to identify the elements and update only the changed elements.
+- In certain situations a missing `key` property can lead to unexpected behavior.

docs/rules/vue-essential/vif-with-vfor.md

@@ -2,3 +2,8 @@
 
 Checks if the component is using `v-if` with `v-for`. &nbsp;&nbsp;<br />
 👉 https://vuejs.org/style-guide/rules-essential.html#avoid-v-if-with-v-for
+
+## ❓ Why it's good to follow this rule?
+
+- **Performance** using `v-if` with `v-for` can lead to performance issues.
+- **Readability** the component is easier to understand and maintain.