When spawning a new atril instance for cross-document links, the
destination and search parameters from the document were interpolated
directly into the command line without shell quoting. Values containing
spaces or special characters could be split into separate arguments by
the shell parser, potentially being interpreted as unintended flags by
the child process.

Apply shell quoting to page label, named destination, and search string
values before appending them to the command line, consistent with how
other spawn sites in the codebase already handle this.

We used to use two methods to save a document: poppler_document_save
and poppler_document_save_a_copy. The latter only saves a copy of
the original document, discarding any change done (e.g. forms and
annotations). However, after a document has been modified and saved,
if there is no new change and the user saves the document, it will
discard even the previous saved changes to preserve a copy of the
original document.

By only using poppler_document_save to save the content of the
current document opened in Atril, to avoid data loss made between
saves.

https://bugzilla.gnome.org/show_bug.cgi?id=770012

Adapted from the original commit at:
https://gitlab.gnome.org/GNOME/evince/-/commit/26dc2f52

Co-authored-by: Eric Park <me@ericswpark.com>

libxml 2.12.0 reorganized headers, resulting in xmlParseFile and xmlIndentTreeOutput no longer being in scope.
Let’s add the proper includes containing the symbols.

* fix a incompatible pointer type warning for gcc14

Co-authored-by: Colomban Wendling <cwendling@hypra.fr>

This commit also fixes an incorrect sizeof call detected by
AddressSanitizer.

Closes #599