Render captions to m.file, m.image, m.video, and m.audio (#2059)

* Add rendering image captions

* Handle sending captions for images

* Fix caption rendering on m.video and m.audio too

* Remove unused renderBody() parameter

* Fix m.file rendering body instead of filename where possible

* Add caption rendering for generic files

+ Fix video and audio not properly sending captions

* Use m.text for captions & render on demand

* Allow custom HTML in sending captions

* Don't *send* captions

* mvoe content const into renderCaption()

---------

Co-authored-by: Ajay Bura <32841439+ajbura@users.noreply.github.com>

src/app/components/message/MsgTypeRenderers.tsx

@@ -172,6 +172,7 @@ export function MNotice({ edited, content, renderBody, renderUrlsPreview }: MNot
 
 type RenderImageContentProps = {
   body: string;
+  filename?: string;
   info?: IImageInfo & IThumbnailContent;
   mimeType?: string;
   url: string;
@@ -282,7 +283,7 @@ export function MAudio({ content, renderAsFile, renderAudioContent, outlined }:
   return (
     <Attachment outlined={outlined}>
       <AttachmentHeader>
-        <FileHeader body={content.body ?? 'Audio'} mimeType={safeMimeType} />
+        <FileHeader body={content.filename ?? content.body ?? 'Audio'} mimeType={safeMimeType} />
       </AttachmentHeader>
       <AttachmentBox>
         <AttachmentContent>
@@ -322,14 +323,14 @@ export function MFile({ content, renderFileContent, outlined }: MFileProps) {
     <Attachment outlined={outlined}>
       <AttachmentHeader>
         <FileHeader
-          body={content.body ?? 'Unnamed File'}
+          body={content.filename ?? content.body ?? 'Unnamed File'}
           mimeType={fileInfo?.mimetype ?? FALLBACK_MIMETYPE}
         />
       </AttachmentHeader>
       <AttachmentBox>
         <AttachmentContent>
           {renderFileContent({
-            body: content.body ?? 'File',
+            body: content.filename ?? content.body ?? 'File',
             info: fileInfo ?? {},
             mimeType: fileInfo?.mimetype ?? FALLBACK_MIMETYPE,
             url: mxcUrl,