Add "Paste element information" to copy one symbol's details onto others

Issue #1375: replacing a symbol meant retyping its label, manufacturer,
part number and the rest by hand. Copy the old symbol (Ctrl+C), select
the new one(s), then Edit > Paste element information, also in the
right-click menu of a selection.

Every field filled in on the copied symbol overwrites the same field on
each selected symbol; fields it leaves empty are left alone, since empty
fields are not written to the clipboard. The label and its formula move
together, so a target whose label comes from a formula takes the copied
label rather than rebuilding its own. A numbering-scheme id is kept only
if the scheme exists in the target project. Plain slaves and folio
reports are skipped: they take their information from what they are
linked to, as in the properties dialog. One undo step.

Enabled only when the clipboard holds exactly one symbol. The clipboard
is parsed once when it changes, not on every selection change.

No default shortcut: Ctrl+Shift+V, suggested in the issue, is already
"Paste at origin". It can be assigned in the shortcut settings.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

sources/diagramview.cpp

@@ -1846,6 +1846,7 @@ QList<QAction *> DiagramView::contextMenuActions() const
 			list << qde->m_cut;
 			list << qde->m_copy;
 			list << m_multi_paste;
+			list << qde->m_paste_element_info;
 			list << m_separators.at(0);
 			list << m_create_template; // Add the create template action
 				//Disabled, and so left out below, unless a selected element