Update scalafmtAll command description

- Change comment from 'Format Scala test code' to 'Format all Scala and sbt code'
- More accurately reflects what scalafmtAll does (formats all Scala files, not just tests)
- Apply change to both README.md and CLAUDE.md for consistency

Author: xerial

CLAUDE.md

@@ -31,7 +31,7 @@ MessagePack-Java is a binary serialization library that provides a fast and comp
 ### Code Quality
 ```bash
 ./sbt jcheckStyle          # Run checkstyle (Facebook Presto style)
-./sbt scalafmtAll          # Format Scala test code
+./sbt scalafmtAll          # Format all Scala and sbt code
 ```
 
 ### Publishing

README.md

@@ -84,7 +84,7 @@ Here is a list of sbt commands for daily development:
 > project msgpack-core                     # Focus on a specific project
 > package                                  # Create a jar file in the target folder of each project
 > jcheckStyle                              # Run check style
-> scalafmtAll                              # Reformat code
+> scalafmtAll                              # Format all Scala and sbt code
 ```
 
 ### Publishing