Fix typo in argument name.

diff --git a/src/doc/external-tools.md b/src/doc/external-tools.md
index fc3c5a3688fc70930e6c28c2ea301b41cee537f8..99f9fde6ab2d0c679e26b2606c168f1f3f004073 100644 (file)
--- a/src/doc/external-tools.md
+++ b/src/doc/external-tools.md
@@ -70,7 +70,7 @@ If you are using Rust, there is [cargo_metadata] crate.
 
 # Information about build
 
-When passing `--message=format=json`, Cargo will output the following
+When passing `--message-format=json`, Cargo will output the following
 information during the build:
 
 * compiler errors and warnings,