stream-clone: add the `-exp` prefix to the bundle part

We forget to do so in 58adcabc295f, however this is important to prevent
"current" client to send incompatible version to future client.

mercurial/bundle2.py

@@ -1952,7 +1952,7 b' def addpartbundlestream2(bundler, repo, '
         )
         requirements = streamclone.streamed_requirements(repo)
         requirements = _formatrequirementsspec(requirements)
-        part = bundler.newpart(b'stream3', data=it)
+        part = bundler.newpart(b'stream3-exp', data=it)
         part.addparam(b'bytecount', b'%d' % bytecount, mandatory=True)
         part.addparam(b'filecount', b'%d' % filecount, mandatory=True)
         part.addparam(b'requirements', requirements, mandatory=True)
@@ -2611,7 +2611,7 b' def handlestreamv2bundle(op, part):'
     streamclone.applybundlev2(repo, part, filecount, bytecount, requirements)
 
 
-@parthandler(b'stream3', (b'requirements', b'filecount', b'bytecount'))
+@parthandler(b'stream3-exp', (b'requirements', b'filecount', b'bytecount'))
 def handlestreamv3bundle(op, part):
     return handlestreamv2bundle(op, part)
 

tests/test-clone-stream.t

@@ -564,7 +564,7 b' Clone with background file closing enabl'
   streaming all changes
   sending getbundle command
   bundle2-input-bundle: with-transaction
-  bundle2-input-part: "stream3" (params: 3 mandatory) supported
+  bundle2-input-part: "stream3-exp" (params: 3 mandatory) supported
   applying stream bundle
   1093 files to transfer, 102 KB of data (no-zstd !)
   1093 files to transfer, 98.9 KB of data (zstd !)