Fix duplicate pgMar causing line numbering issue

- Update existing pgMar instead of appending a second one
- Prevents Word from miscounting lines on first page

scraibe/email_sender.py

@@ -322,7 +322,10 @@ def _create_transcript_section_properties(section):
     sectPr = section._sectPr
 
     # Margins: 1 inch = 1440 twips
-    pgMar = sectPr.find(f"{{{W_NS}}}pgMar") or OxmlElement("w:pgMar")
+    pgMar = sectPr.find(f"{{{W_NS}}}pgMar")
+    if pgMar is None:
+        pgMar = OxmlElement("w:pgMar")
+        sectPr.append(pgMar)
     _set_element_attr(pgMar, "top", "1440")
     _set_element_attr(pgMar, "right", "1440")
     _set_element_attr(pgMar, "bottom", "1440")
@@ -330,7 +333,6 @@ def _create_transcript_section_properties(section):
     _set_element_attr(pgMar, "header", "720")
     _set_element_attr(pgMar, "footer", "720")
     _set_element_attr(pgMar, "gutter", "0")
-    sectPr.append(pgMar)
 
     # Disable document grid to avoid Word counting phantom grid lines
     docGrid = sectPr.find(f"{{{W_NS}}}docGrid")