Merge pull request #21135 from Shourya742/2025-11-26-default-json

fix: Fix proc-macro-srv protocol read implementation

src/tools/rust-analyzer/crates/proc-macro-api/src/legacy_protocol/msg.rs

@@ -152,7 +152,7 @@ pub trait Message: serde::Serialize + DeserializeOwned {
     fn read<R: BufRead, C: Codec>(inp: &mut R, buf: &mut C::Buf) -> io::Result<Option<Self>> {
         Ok(match C::read(inp, buf)? {
             None => None,
-            Some(buf) => C::decode(buf)?,
+            Some(buf) => Some(C::decode(buf)?),
         })
     }
     fn write<W: Write, C: Codec>(self, out: &mut W) -> io::Result<()> {