A `schemaType` of `integer` doesn't seem to work correctly with custom keyword

**What version of Ajv are you using? Does the issue happen if you use the latest version?**

8.6.2

**Ajv options object**

```javascript
{
strict: true,
allErrors: true,
logger: console,
loadSchema: () => {},
}
```

**JSON Schema**

```json
{
"myBadKeyword": 5,
}
```

**Your code**

```javascript
const Ajv = require('ajv');

async function testIt() {
const ajvOptions = {
strict: true,
allErrors: true,
logger: console,
loadSchema: () => {},
};

const ajv = new Ajv(ajvOptions);
ajv.addKeyword({
keyword: 'myBadKeyword',
schemaType: 'integer',
});

ajv.addKeyword({
keyword: 'myGoodKeyword',
schemaType: 'number',
});

const myBadSchema = {
myBadKeyword: 5,
};

const myGoodSchema = {
myGoodKeyword: 5,
};

try {
await ajv.compileAsync(myBadSchema);
console.log('bad schema compiled without exception');
} catch (e) {
console.log(e);
}

try {
await ajv.compileAsync(myGoodSchema);
console.log('good schema compiled without exception');
} catch (e) {
console.log(e);
}
}

testIt().then(console.log('done'));
```

Output:

```bash
✗ node test.js
done
Error: myBadKeyword value must be ["integer"]
at new KeywordCxt (/Users/cwelchmi/repos/metasys-rest-api/node_modules/ajv/dist/compile/validate/index.js:298:23)
at keywordCode (/Users/cwelchmi/repos/metasys-rest-api/node_modules/ajv/dist/compile/validate/index.js:449:17)
at /Users/cwelchmi/repos/metasys-rest-api/node_modules/ajv/dist/compile/validate/index.js:222:17
at CodeGen.code (/Users/cwelchmi/repos/metasys-rest-api/node_modules/ajv/dist/compile/codegen/index.js:439:13)
at CodeGen.block (/Users/cwelchmi/repos/metasys-rest-api/node_modules/ajv/dist/compile/codegen/index.js:568:18)
at iterateKeywords (/Users/cwelchmi/repos/metasys-rest-api/node_modules/ajv/dist/compile/validate/index.js:219:9)
at groupKeywords (/Users/cwelchmi/repos/metasys-rest-api/node_modules/ajv/dist/compile/validate/index.js:208:13)
at /Users/cwelchmi/repos/metasys-rest-api/node_modules/ajv/dist/compile/validate/index.js:192:13
at CodeGen.code (/Users/cwelchmi/repos/metasys-rest-api/node_modules/ajv/dist/compile/codegen/index.js:439:13)
at CodeGen.block (/Users/cwelchmi/repos/metasys-rest-api/node_modules/ajv/dist/compile/codegen/index.js:568:18)
good schema compiled without exception
```

**Validation result, data AFTER validation, error messages**

Compiling the good schema with a custom keyword using `schemaType` of `number` works fine. Compiling the bad schema with a custom keyword using `schemaType` of `integer` throws an exception even though the data in the schema is an integer.

**What results did you expect?**

I expected that I could use `schemaType` of integer in this case.

**Are you going to resolve the issue?**

I just started looking into the issue. Not familiar with the code base, so I'm not sure.