Add consistent option to vue/padding-line-between-tags docs (#2003)

Author: FloEdelmann

docs/rules/padding-line-between-tags.md

@@ -52,11 +52,12 @@ This rule requires or disallows newlines between sibling HTML tags.
 
 This rule requires blank lines between each sibling HTML tag by default.
 
-A configuration is an object which has 3 properties; blankLine, prev and next. For example, { blankLine: "always", prev: "br", next: "div" } means “one or more blank lines are required between a br tag and a div tag.” You can supply any number of configurations. If a tag pair matches multiple configurations, the last matched configuration will be used.
+A configuration is an object which has 3 properties; `blankLine`, `prev` and `next`. For example, `{ blankLine: "always", prev: "br", next: "div" }` means “one or more blank lines are required between a `br` tag and a `div` tag.” You can supply any number of configurations. If a tag pair matches multiple configurations, the last matched configuration will be used.
 
 - `blankLine` is one of the following:
   - `always` requires one or more blank lines.
   - `never` disallows blank lines.
+  - `consistent` requires or disallows a blank line based on the first sibling element.
 - `prev` any tag name without brackets.
 - `next` any tag name without brackets.
 
@@ -106,12 +107,12 @@ A configuration is an object which has 3 properties; blankLine, prev and next. F
 
 </eslint-code-block>
 
-### Require newlines before `<br>`
+### Require newlines between `<br>` and `<img>`
 
-`{ blankLine: 'always', prev: '*', next: 'br' }`
+`{ blankLine: 'always', prev: 'br', next: 'img' }`
 
 <eslint-code-block fix :rules="{'vue/padding-line-between-tags': ['error', [
-  { blankLine: 'always', prev: '*', next: 'br' }
+  { blankLine: 'always', prev: 'br', next: 'img' }
 ]]}">
 
 ```vue
@@ -120,8 +121,9 @@ A configuration is an object which has 3 properties; blankLine, prev and next. F
     <ul>
       <li>
       </li>
-      
       <br />
+
+      <img />
       <li>
       </li>
     </ul>
@@ -131,26 +133,26 @@ A configuration is an object which has 3 properties; blankLine, prev and next. F
 
 </eslint-code-block>
 
-### Require newlines between `<br>` and `<img>`
+### Require consistent newlines
 
-`{ blankLine: 'always', prev: 'br', next: 'img' }`
+`{ blankLine: 'consistent', prev: '*', next: '*' }`
 
 <eslint-code-block fix :rules="{'vue/padding-line-between-tags': ['error', [
-  { blankLine: 'always', prev: 'br', next: 'img' }
+  { blankLine: 'consistent', prev: '*', next: '*' }
 ]]}">
 
 ```vue
 <template>
   <div>
     <ul>
-      <li>
-      </li>
-      <br />
-
-      <img />
-      <li>
-      </li>
+      <li />
+      <li />
+      <li />
     </ul>
+    
+    <div />
+    
+    <div />
   </div>
 </template>
 ```