man/nitmetrics.md: add missing `--detect-covariance`

Signed-off-by: Jean Privat <jean@pryen.org>

diff --git a/share/man/nitmetrics.md b/share/man/nitmetrics.md
index 0277161..1841d61 100644 (file)
--- a/share/man/nitmetrics.md
+++ b/share/man/nitmetrics.md
@@ -57,6 +57,9 @@ Detects the definition-site variance constraints on formal parameters.
 
 Infers the possible variance annotations of formal types in Nit programs by identifying the existing constraints on the usage of those formal type.
 
+### `--detect-covariance`
+Detect the static covariance usages.
+
 ## OUTPUT
 
 ### `--csv`