fix: use h1 for title heading to improve accessibility (#10598)

Fixes #10480

Author: SkullShoT007

src/core/components/info.jsx

@@ -97,13 +97,13 @@ class Info extends React.Component {
     return (
       <div className="info">
         <hgroup className="main">
-          <h2 className="title">
+          <h1 className="title">
             {title}
             <span>
               {version && <VersionStamp version={version} />}
               <OpenAPIVersion oasVersion="2.0" />
             </span>
-          </h2>
+          </h1>
           {host || basePath ? (
             <InfoBasePath host={host} basePath={basePath} />
           ) : null}

src/core/plugins/oas31/components/info.jsx

@@ -33,13 +33,13 @@ const Info = ({ getComponent, specSelectors }) => {
   return (
     <div className="info">
       <hgroup className="main">
-        <h2 className="title">
+        <h1 className="title">
           {title}
           <span>
             {version && <VersionStamp version={version} />}
             <OpenAPIVersion oasVersion="3.1" />
           </span>
-        </h2>
+        </h1>
 
         {(host || basePath) && <InfoBasePath host={host} basePath={basePath} />}
         {url && <InfoUrl getComponent={getComponent} url={url} />}

test/e2e-cypress/e2e/bugs/5138.cy.js

@@ -2,7 +2,7 @@ describe("#5138: unwanted `url`/`urls` interactions", () => {
   it("should stably render the first `urls` entry", () => {
     cy
       .visit("/pages/5138/")
-      .get("h2.title")
+      .get("h1.title")
       .contains("USPTO Data Set API")
       .wait(3000)
       .contains("USPTO Data Set API")

test/e2e-cypress/e2e/features/urls.cy.js

@@ -19,7 +19,7 @@ describe("configuration options: `urls` and `urls.primaryName`", () => {
 
     it("should render the first URL in the list", () => {
       cy.visit("/?configUrl=/configs/urls.yaml")
-        .get("h2.title")
+        .get("h1.title")
         .should("have.text", "OneOAS 2.0")
         .window()
         .then(win => win.ui.specSelectors.url())
@@ -31,7 +31,7 @@ describe("configuration options: `urls` and `urls.primaryName`", () => {
     cy.visit("/?configUrl=/configs/urls-primary-name.yaml")
       .get("select")
       .should("contain.value", "/documents/features/urls/2.yaml")
-      .get("h2.title")
+      .get("h1.title")
       .should("have.text", "TwoOAS 3.0")
       .window()
       .then(win => win.ui.specSelectors.url())