[DOCS] Adjust name for PageTitle API in documentation

The funtionality was named titleTag before. But the new API is
called PageTitle API.

Resolves: #89940
Releases: master, 9.5
Change-Id: Idd42c5c5f53d999351c787ac7edb474795132f48
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/62625


Tested-by: Björn Jacob <bjoern.jacob@tritum.de>
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Guido Schmechel <guido.schmechel@brandung.de>
Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: Daniel Goerz <daniel.goerz@posteo.de>
Reviewed-by: Björn Jacob <bjoern.jacob@tritum.de>
Reviewed-by: Guido Schmechel <guido.schmechel@brandung.de>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Daniel Goerz <daniel.goerz@posteo.de>

typo3/sysext/core/Documentation/Changelog/9.4/Deprecation-85678-ConfigTitleTagFunction.rst

@@ -27,6 +27,6 @@ Instances using the option.
 Migration
 =========
 
-Please use the new TitleTag API to alter the title tag.
+Please use the new PageTitle API to alter the title tag.
 
 .. index:: TypoScript, NotScanned

typo3/sysext/core/Documentation/Changelog/9.4/Deprecation-85678-TsfeAltPageTitle.rst

@@ -27,6 +27,6 @@ Instances using the property.
 Migration
 =========
 
-Please use the new TitleTag API to alter the title tag.
+Please use the new PageTitle API to alter the title tag.
 
 .. index:: TypoScript, NotScanned