fix: text in doc version banner (#105)

Uses `see the Current version` text over `latest version` to refer to
Fluvio Stable.

<img width="1512" alt="Screenshot 2024-07-18 at 7 37 00 PM"
src="https://github.com/user-attachments/assets/79a7bf44-d27b-4288-88bf-a8f0d40711c7">

src/theme/DocVersionBanner/index.tsx

@@ -0,0 +1,171 @@
+import React, {type ComponentType} from 'react';
+import clsx from 'clsx';
+import useDocusaurusContext from '@docusaurus/useDocusaurusContext';
+import Link from '@docusaurus/Link';
+import Translate from '@docusaurus/Translate';
+import {
+  useActivePlugin,
+  useDocVersionSuggestions,
+  type GlobalVersion,
+} from '@docusaurus/plugin-content-docs/client';
+import {ThemeClassNames} from '@docusaurus/theme-common';
+import {
+  useDocsPreferredVersion,
+  useDocsVersion,
+} from '@docusaurus/theme-common/internal';
+import type {Props} from '@theme/DocVersionBanner';
+import type {
+  VersionBanner,
+  PropVersionMetadata,
+} from '@docusaurus/plugin-content-docs';
+
+type BannerLabelComponentProps = {
+  siteTitle: string;
+  versionMetadata: PropVersionMetadata;
+};
+
+function UnreleasedVersionLabel({
+  siteTitle,
+  versionMetadata,
+}: BannerLabelComponentProps) {
+  return (
+    <Translate
+      id="theme.docs.versions.unreleasedVersionLabel"
+      description="The label used to tell the user that he's browsing an unreleased doc version"
+      values={{
+        siteTitle,
+        versionLabel: <b>{versionMetadata.label}</b>,
+      }}>
+      {
+        'This is unreleased documentation for {siteTitle} {versionLabel} version.'
+      }
+    </Translate>
+  );
+}
+
+function UnmaintainedVersionLabel({
+  siteTitle,
+  versionMetadata,
+}: BannerLabelComponentProps) {
+  return (
+    <Translate
+      id="theme.docs.versions.unmaintainedVersionLabel"
+      description="The label used to tell the user that he's browsing an unmaintained doc version"
+      values={{
+        siteTitle,
+        versionLabel: <b>{versionMetadata.label}</b>,
+      }}>
+      {
+        'This is documentation for {siteTitle} {versionLabel}, which is no longer actively maintained.'
+      }
+    </Translate>
+  );
+}
+
+const BannerLabelComponents: {
+  [banner in VersionBanner]: ComponentType<BannerLabelComponentProps>;
+} = {
+  unreleased: UnreleasedVersionLabel,
+  unmaintained: UnmaintainedVersionLabel,
+};
+
+function BannerLabel(props: BannerLabelComponentProps) {
+  const BannerLabelComponent =
+    BannerLabelComponents[props.versionMetadata.banner!];
+  return <BannerLabelComponent {...props} />;
+}
+
+function LatestVersionSuggestionLabel({
+  versionLabel,
+  to,
+  onClick,
+}: {
+  to: string;
+  onClick: () => void;
+  versionLabel: string;
+}) {
+  return (
+    <Translate
+      id="theme.docs.versions.latestVersionSuggestionLabel"
+      description="The label used to tell the user to check the latest version"
+      values={{
+        versionLabel,
+        latestVersionLink: (
+          <b>
+            <Link to={to} onClick={onClick}>
+              <Translate
+                id="theme.docs.versions.latestVersionLinkLabel"
+                description="The label used for the latest version suggestion link label">
+                see the Current version
+              </Translate>
+            </Link>
+          </b>
+        ),
+      }}>
+      {
+        'For up-to-date documentation, see the {latestVersionLink} ({versionLabel}).'
+      }
+    </Translate>
+  );
+}
+
+function DocVersionBannerEnabled({
+  className,
+  versionMetadata,
+}: Props & {
+  versionMetadata: PropVersionMetadata;
+}): JSX.Element {
+  const {
+    siteConfig: {title: siteTitle},
+  } = useDocusaurusContext();
+  const {pluginId} = useActivePlugin({failfast: true})!;
+
+  const getVersionMainDoc = (version: GlobalVersion) =>
+    version.docs.find((doc) => doc.id === version.mainDocId)!;
+
+  const {savePreferredVersionName} = useDocsPreferredVersion(pluginId);
+
+  const {latestDocSuggestion, latestVersionSuggestion} =
+    useDocVersionSuggestions(pluginId);
+
+  // Try to link to same doc in latest version (not always possible), falling
+  // back to main doc of latest version
+  const latestVersionSuggestedDoc =
+    latestDocSuggestion ?? getVersionMainDoc(latestVersionSuggestion);
+
+  return (
+    <div
+      className={clsx(
+        className,
+        ThemeClassNames.docs.docVersionBanner,
+        'alert alert--warning margin-bottom--md',
+      )}
+      role="alert">
+      <div>
+        <BannerLabel siteTitle={siteTitle} versionMetadata={versionMetadata} />
+      </div>
+      <div className="margin-top--md">
+        <LatestVersionSuggestionLabel
+          versionLabel={latestVersionSuggestion.label}
+          to={latestVersionSuggestedDoc.path}
+          onClick={() => savePreferredVersionName(latestVersionSuggestion.name)}
+        />
+      </div>
+    </div>
+  );
+}
+
+export default function DocVersionBanner({
+  className,
+}: Props): JSX.Element | null {
+  const versionMetadata = useDocsVersion();
+  if (versionMetadata.banner) {
+    return (
+      <DocVersionBannerEnabled
+        className={className}
+        versionMetadata={versionMetadata}
+      />
+    );
+  }
+  return null;
+}