man: add --detect-variance-constraints in nitmetrics.md

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

diff --git a/share/man/nitmetrics.md b/share/man/nitmetrics.md
index 9b01489..dcdb67c 100644 (file)
--- a/share/man/nitmetrics.md
+++ b/share/man/nitmetrics.md
@@ -54,6 +54,11 @@ nitmetrics [*options*]... FILE...
 `--poset`
 :   Complete metrics on posets
 
+`--detect-variance-constraints`
+:   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.
+
 ## OUTPUT
 
 `--csv`