chore: Tweak punctuation in variables6.rs hint

While the meaning is still obvious as is, it makes a little more sense
to use a colon here =)

1 files changed, 1 insertions, 1 deletions

diff --git a/info.toml b/info.toml
index 042172d..d790643 100644
--- a/info.toml
+++ b/info.toml
@@ -79,7 +79,7 @@ path = "exercises/variables/variables6.rs"
 mode = "compile"
 hint = """
 We know about variables and mutability, but there is another important type of
-variable available; constants.
+variable available: constants.
 Constants are always immutable and they are declared with keyword 'const' rather
 than keyword 'let'.
 Constants types must also always be annotated.