fix: Improve violation reporting location for no-unused-placeholders (#279)

* fix: reporting location for no-unused-placeholders

* improve test

Author: bmish

Diff for: lib/rules/no-unused-placeholders.js

@@ -108,7 +108,7 @@ module.exports = {
                 const key = utils.getKeyName(prop);
                 if (!placeholdersInMessage.has(key)) {
                   context.report({
-                    node: message,
+                    node: prop,
                     messageId: 'placeholderUnused',
                     data: { unusedKey: key },
                   });

Diff for: tests/lib/rules/no-missing-placeholders.js

@@ -236,7 +236,19 @@ ruleTester.run('no-missing-placeholders', rule, {
           }
         };
       `,
-      errors: [error('bar', 'Literal')],
+      errors: [
+        error(
+          'bar',
+          'Literal',
+          // report on `message`
+          {
+            line: 6,
+            endLine: 6,
+            column: 24,
+            endColumn: 37,
+          }
+        ),
+      ],
     },
     {
       code: `

Diff for: tests/lib/rules/no-unused-placeholders.js

@@ -17,10 +17,11 @@ const RuleTester = require('eslint').RuleTester;
  * @param {string} unusedKey The placeholder that is unused
  * @returns {object} An expected error
  */
-function error(unusedKey, type = 'Literal') {
+function error(unusedKey, extra) {
   return {
-    type,
+    type: 'Property', // The property in the report's `data` object for the unused placeholder.
     message: `The placeholder {{${unusedKey}}} is unused (does not exist in the actual message).`,
+    ...extra,
   };
 }
 
@@ -211,7 +212,18 @@ ruleTester.run('no-unused-placeholders', rule, {
           }
         };
       `,
-      errors: [error('bar')],
+      errors: [
+        error(
+          'bar',
+          // report on property in data object
+          {
+            line: 7,
+            endLine: 7,
+            column: 23,
+            endColumn: 26,
+          }
+        ),
+      ],
     },
     {
       // With `create` as variable.
@@ -241,7 +253,7 @@ ruleTester.run('no-unused-placeholders', rule, {
           }
         };
       `,
-      errors: [error('bar', 'Identifier')],
+      errors: [error('bar')],
     },
     {
       code: `