Rule proposal: `no-useless-interpolation`

Hi there! 👋 First of all, thanks again for this plugin, super helpful, the things available in this plugin.

I wanted to propose a new rule to address a pattern that I have seen from a lot of our students at @upleveled - writing overly complex patterns with unnecessary interpolations in template strings (eg. a single string variable, or a string literal, or multiple string literals).

Fail

const withString = `${str}`;
const withStringLiteral = `${'abc'}`;
const withMultipleStringLiterals = `${'abc'}${'def'}`;

Pass

const withString = str;
const withStringLiteral = 'abc';
const withMultipleStringLiterals = 'abcdef';

Implementation ideas

Looking into the ASTExplorer, I guess the simple version of the first failure case below would be:

• only 1 element in TemplateLiteral.expressions (an Identifier)
• only 2 elements in TemplateLiteral.quasis, all empty strings

For the literals, I guess no limit to the quasis, but every element in expressions should be a Literal.

[fisker]

The rule could be two parts

1. forbid string literal as expression.
2. No expression-only template.

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Update:

String concatenation should fobid too

`before${ "head" + expression + "tail" }after`

[fisker]

One note, taged templates should not reported.