title: add 'description' to Pydantic schema when using pydantic.dataclasses
body: <p><code>Pydantic</code> supports generating OpenApi/jsonschema schemas.  When using Pydantic's <code>BaseModel</code> to define models one can add <code>description</code> and <code>title</code> to the resultant json/yaml spec.</p>
  <pre><code>class DescriptionFromBasemodel(BaseModel):
      with_desc: int = Field(
          42,
          title='my title',
          description='descr text',)
  </code></pre>
  <p>and this is carried over to the schema: <code>DescriptionFromBasemodel.schema_json()</code></p>
  <pre><code>{
      ... schema title, description, type top-level ...
      &quot;properties&quot;: {
          &quot;with_desc&quot;: {
              &quot;title&quot;: &quot;my title&quot;,
              &quot;description&quot;: &quot;descr text&quot;,
              &quot;type&quot;: ...
         ...
  </code></pre>
  <p>however, I cannot determine how to plumb this using <code>pydantic.dataclasses</code> which my application must use to play nicely elsewhere.  you can add <code>metadata</code> to stdlib <code>dataclass</code> <code>Field(...)</code>s, but pydantic does not use them (?)</p>
  <pre><code>from pydantic.dataclasses import dataclass
  from dataclasses import field
  
  @dataclass
  class DataclassWithDescription:
     a_field: int = field(metadata=dict(
         description=&quot;descr text&quot;))
  </code></pre>
  <p>and no <code>description</code> is generated output using <code>DataclassWithDescription.__pydantic_model__.schema_json()</code></p>