feat: introduce rule to check for .ts extension

docs/rules/no-dot-ts-import.md

@@ -0,0 +1,54 @@
+---
+title: '@rotki/no-dot-ts-import'
+description: description
+since: v0.6.0
+---
+
+# @rotki/no-dot-ts-import
+
+> description
+
+## :book: Rule Details
+
+This rule reports the usage of the .ts extension when importing dependencies.
+
+- :black_nib:️ The `--fix` option on the [command line](http://eslint.org/docs/user-guide/command-line-interface#fix) can automatically fix some of the problems reported by this rule.
+
+<eslint-code-block>
+
+<!-- eslint-skip -->
+
+```vue
+<!-- ✓ GOOD -->
+<script lang="ts" setup>
+  /* eslint @rotki/no-dot-ts-import: "error" */
+  import { something } from '@/packages/something';
+</script>
+
+<!-- ✗ BAD -->
+<script lang="ts" setup>
+  /* eslint @rotki/no-dot-ts-import: "error" */
+  import { something } from '@/packages/something.ts';
+</script>
+```
+
+</eslint-code-block>
+
+## :gear: Options
+
+```json
+{
+  "@rotki/no-dot-ts-import": ["error"]
+}
+```
+
+-
+
+## :rocket: Version
+
+This rule was introduced in `@rotki/eslint-plugin` v0.6.0
+
+## :mag: Implementation
+
+- [Rule source](https://github.com/rotki/eslint-plugin/blob/master/src/rules/no-dot-ts-import.ts)
+- [Test source](https://github.com/rotki/eslint-plugin/tree/master/tests/rules/no-dot-ts-import.ts)

src/rules/no-dot-ts-import.ts

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+import { createEslintRule } from '../utils';
+
+export const RULE_NAME = 'no-dot-ts-import';
+
+export type MessageIds = 'invalidTSExtension';
+
+export type Options = [];
+
+export default createEslintRule<Options, MessageIds>({
+  create(context) {
+    return {
+      ImportDeclaration(node) {
+        const importDeclaration = node.source.value;
+        if (!importDeclaration.endsWith('.ts'))
+          return;
+
+        const lastIndexOfExtension = importDeclaration.lastIndexOf('.ts');
+        const replacement = importDeclaration.substring(0, lastIndexOfExtension);
+
+        context.report({
+          data: {
+            import: importDeclaration,
+          },
+          fix(fixer) {
+            return fixer.replaceText(node.source, `'${replacement}'`);
+          },
+          messageId: 'invalidTSExtension',
+          node: node.source,
+        });
+      },
+    };
+  },
+  defaultOptions: [],
+  meta: {
+    docs: {
+      description: 'Checks and replaces .ts extension in import statements.',
+    },
+    fixable: 'code',
+    messages: {
+      invalidTSExtension: `'{{ import }}' has a .ts extension, please remove it'`,
+    },
+    schema: [],
+    type: 'problem',
+  },
+  name: RULE_NAME,
+});

tests/rules/no-dot-ts-import.ts

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+import { RuleTester } from 'eslint';
+import vueParser from 'vue-eslint-parser';
+import rule from '../../src/rules/no-dot-ts-import';
+
+const tester = new RuleTester({
+  languageOptions: {
+    parser: vueParser,
+    parserOptions: {
+      ecmaVersion: 2020,
+      sourceType: 'module',
+    },
+  },
+});
+
+tester.run('no-dot-ts-import', rule as never, {
+  valid: [
+    {
+      filename: 'test.vue',
+      code: `
+        <script lang="ts" setup>
+        import { something } from '@/packages/something'; 
+        </script>        
+      `.trim(),
+    },
+  ],
+  invalid: [
+    {
+      filename: 'test.vue',
+      code: `
+        <script lang="ts" setup>
+        import { something } from '@/packages/something.ts'; 
+        </script>               
+      `.trim(),
+      output: `
+        <script lang="ts" setup>
+        import { something } from '@/packages/something'; 
+        </script>               
+      `.trim(),
+      errors: [
+        {
+          messageId: 'invalidTSExtension',
+        },
+      ],
+    },
+  ],
+});