M4: Document Properties has a Custom tab for custom properties (#4387)

* M4: Document Properties has a Custom tab for custom properties

Document Properties has a new Custom tab between Fonts and Advanced. It
lists the document's custom properties, and Name and Value fields with
Add, Update and Delete edit the list. Clicking a listed property fills
the fields with it. OK writes the changes through SetInfo in the
existing "Change document properties" step, so one undo reverts them
with the other tabs' changes.

Add is off for an empty value, a name already listed, a name that
check_custom_key refuses (its message is the button's tooltip), and a
name the file already uses for an entry the list leaves out (not text,
only padding, or past the 256 listed). A property already in the file
under a refused name or a name that is not UTF-8 is listed, and Add,
Update and Delete stay off for it, so OK cannot fail on it or write a
different key.

Clearing an /Info entry now removes it when /Info is a dictionary
written directly in the trailer. set_info_entry returned without a
change there, so a delete in the Custom tab, a cleared Description field
and a doc_set_info clear left the entry in the file. It now writes a
copy without the entry as a new indirect /Info.

The engine re-exports check_custom_key and adds Document::has_info
(organize::has_info). set_option("dialog", "custom") opens the tab.

* Contributors: add dotCooCoo (Robert Lee)

* M4: Add in the Custom tab stops at the 256 properties the tab lists

Document Properties > Custom lists at most 256 properties, so a property
added past that was saved but left out of the list when the dialog opened
again. Add is now off once the tab's list or the file's own list holds 256;
a new name goes after the file's entries, so a file with more than 256 keeps
Add off after a Delete as well.

parity/acrobat-features.toml

@@ -3517,10 +3517,10 @@ area = "D"
 tier = "P2"
 milestone = "M4"
 status = "partial"
-commands = []
+commands = ["file.properties"]
 tools = ["doc_info", "doc_set_info"]
-evidence = ["crates/organize/src/tests.rs::custom_document_properties_are_listed_set_removed_and_their_names_checked", "crates/render/src/inspect.rs::custom_document_properties_are_listed_apart_from_the_standard_ones", "crates/automation/tests/it/automation.rs::custom_document_properties_are_set_listed_and_cleared_through_the_tools"]
-notes = "Through the tools: doc_set_info sets or clears an /Info entry under any name the spec does not use (names checked as Acrobat does: no standard name, no empty name, no spaces or delimiters, at most 127 bytes), and doc_info lists them under custom, apart from the standard entries. Not yet: the Custom tab in Document Properties, and mirroring them into XMP (pdfx:) as Acrobat does"
+evidence = ["crates/organize/src/tests.rs::custom_document_properties_are_listed_set_removed_and_their_names_checked", "crates/render/src/inspect.rs::custom_document_properties_are_listed_apart_from_the_standard_ones", "crates/automation/tests/it/automation.rs::custom_document_properties_are_set_listed_and_cleared_through_the_tools", "crates/ui-egui/tests/it/editing.rs::custom_properties_are_added_in_the_custom_tab_as_one_undoable_step", "crates/ui-egui/tests/it/editing.rs::custom_properties_are_changed_and_deleted_in_the_custom_tab", "crates/ui-egui/tests/it/editing.rs::the_custom_tab_refuses_names_a_custom_property_cannot_have", "crates/ui-egui/tests/it/editing.rs::a_custom_property_whose_name_the_tools_refuse_is_listed_and_left_alone", "crates/ui-egui/tests/it/editing.rs::a_custom_property_is_deleted_from_an_info_dictionary_in_the_trailer", "crates/ui-egui/tests/it/editing.rs::add_stops_at_the_256_custom_properties_the_tab_lists", "crates/organize/src/tests.rs::document_info_entries_are_cleared_from_an_info_dictionary_in_the_trailer"]
+notes = "Document Properties ▸ Custom lists them, with Name and Value fields and Add, Update (the value of the listed property the Name field names) and Delete; OK writes the changes as one undo step with the other tabs' changes. A property already in the file under a name the tools refuse (a space, a delimiter) or a name that is not UTF-8 is listed and cannot be changed or deleted there, and Add is off for a name the file already uses for an entry that is not listed (not text, only padding, or past the 256 listed), and once the tab or the file lists 256 properties. Through the tools: doc_set_info sets or clears an /Info entry under any name the spec does not use (names checked as Acrobat does: no standard name, no empty name, no spaces or delimiters, at most 127 bytes), and doc_info lists them under custom, apart from the standard entries. Not yet: mirroring them into XMP (pdfx:) as Acrobat does"
 
 [[feature]]
 id = "organize.xmp-editor"