Undefined pageTitleSuffix causes thes string "undefined" to be appended to page titles

[LesleyLai]

I encountered the same issue as #1445 after updating. The pageTitleSuffix variable is marked as optional so that the type checking won't prevent this issue.

Potential fix 1

This fix ensures that old codes without the pageTitleSuffix field in the configuration continue to work after the update.

quartz\components\Head.tsx

    const title =
-      (fileData.frontmatter?.title ?? i18n(cfg.locale).propertyDefaults.title) + cfg.pageTitleSuffix
+      (fileData.frontmatter?.title ?? i18n(cfg.locale).propertyDefaults.title) + (cfg.pageTitleSuffix ?? "")

Potential fix 2

This fix enforces the requirement to provide a pageTitleSuffix during type checking

quartz\cfg.ts

export interface GlobalConfiguration {
  pageTitle: string
-  pageTitleSuffix?: string
+  pageTitleSuffix: string