Rename CustomPDDocumentFactory to CustomPDFDocumentFactory across multiple controllers (#3163)

# Description of Changes

Please provide a summary of the changes, including:

- What was changed
- Why the change was made
- Any challenges encountered

Closes #(issue_number)

---

## Checklist

### General

- [ ] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [ ] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/HowToAddNewLanguage.md)
(if applicable)
- [ ] I have performed a self-review of my own code
- [ ] My changes generate no new warnings

### Documentation

- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### UI Changes (if applicable)

- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [ ] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md#6-testing)
for more details.

---------

Co-authored-by: Anthony Stirling <77850077+Frooodle@users.noreply.github.com>

src/main/java/stirling/software/SPDF/controller/api/MergeController.java

@@ -33,7 +33,7 @@ import io.swagger.v3.oas.annotations.tags.Tag;
 import lombok.extern.slf4j.Slf4j;
 
 import stirling.software.SPDF.model.api.general.MergePdfsRequest;
-import stirling.software.SPDF.service.CustomPDDocumentFactory;
+import stirling.software.SPDF.service.CustomPDFDocumentFactory;
 import stirling.software.SPDF.utils.GeneralUtils;
 import stirling.software.SPDF.utils.WebResponseUtils;
 
@@ -43,10 +43,10 @@ import stirling.software.SPDF.utils.WebResponseUtils;
 @Tag(name = "General", description = "General APIs")
 public class MergeController {
 
-    private final CustomPDDocumentFactory pdfDocumentFactory;
+    private final CustomPDFDocumentFactory pdfDocumentFactory;
 
     @Autowired
-    public MergeController(CustomPDDocumentFactory pdfDocumentFactory) {
+    public MergeController(CustomPDFDocumentFactory pdfDocumentFactory) {
         this.pdfDocumentFactory = pdfDocumentFactory;
     }
 
@@ -119,7 +119,9 @@ public class MergeController {
     @Operation(
             summary = "Merge multiple PDF files into one",
             description =
-                    "This endpoint merges multiple PDF files into a single PDF file. The merged file will contain all pages from the input files in the order they were provided. Input:PDF Output:PDF Type:MISO")
+                    "This endpoint merges multiple PDF files into a single PDF file. The merged"
+                            + " file will contain all pages from the input files in the order they were"
+                            + " provided. Input:PDF Output:PDF Type:MISO")
     public ResponseEntity<byte[]> mergePdfs(@ModelAttribute MergePdfsRequest form)
             throws IOException {
         List<File> filesToDelete = new ArrayList<>(); // List of temporary files to delete