Revert "Regen paraid (#855)" (#856)

This reverts commit 78d08c6.

Author: bokuweb

docx-core/src/documents/elements/paragraph.rs

@@ -7,7 +7,7 @@ use crate::documents::BuildXML;
 use crate::types::*;
 use crate::xml_builder::*;
 
-#[derive(Serialize, Debug, PartialEq)]
+#[derive(Serialize, Debug, Clone, PartialEq)]
 #[serde(rename_all = "camelCase")]
 pub struct Paragraph {
     pub id: String,
@@ -27,17 +27,6 @@ impl Default for Paragraph {
     }
 }
 
-impl Clone for Paragraph {
-    fn clone(&self) -> Self {
-        Self {
-            id: crate::generate_para_id(), // 新しいIDを生成してID重複を防ぐ
-            children: self.children.clone(),
-            property: self.property.clone(),
-            has_numbering: self.has_numbering,
-        }
-    }
-}
-
 #[derive(Debug, Clone, PartialEq)]
 pub enum ParagraphChild {
     Run(Box<Run>),

docx-core/src/documents/elements/table_of_contents.rs

@@ -228,7 +228,7 @@ impl BuildXML for TableOfContents {
                         TocContent::Paragraph(p) => {
                             // Merge paragraph
                             if i == 0 {
-                                let mut new_p = p.clone(); // cloneで自動的に新しいIDが生成される
+                                let mut new_p = p.clone();
                                 new_p.children.insert(
                                     0,
                                     ParagraphChild::Run(Box::new(