Fix whitespace, comment typos
Update/Fix phpDoc
Fix minor IDE complaints
Fix phpDoc
[BUGFIX] Replace unused command subparts with empty string

If a command execution does not return any variables the subpart will
be replaced with an empty string instead of being not modified at all.
This prevents errors in view helper within the subparts when the main
template is rendered.

Resolves: #55691
[BUGFIX]Restore compatibility for TYPO3 < 6.0
Revert "[TASK] Ensure type of Dynamic fields"

This reverts commit 62566bf022e6828ce05d3754db56fe0a81ba3a51.