fix: spacing around calc

src/Init/NotationExtra.lean

@@ -92,7 +92,7 @@ end
 syntax calcFirstStep := ppIndent(colGe term (" := " term)?)
 -- enforce indentation of calc steps so we know when to stop parsing them
 syntax calcStep := ppIndent(colGe term " := " term)
-syntax calcSteps := ppLine withPosition(calcFirstStep) ppLine withPosition((calcStep ppLine)*)
+syntax calcSteps := ppLine withPosition(calcFirstStep) withPosition((ppLine calcStep)*)
 
 /-- Step-wise reasoning over transitive relations.
 ```

tests/lean/formatTerm.lean

@@ -59,3 +59,7 @@ def foo : a b c d e f g a b c d e f g h where
   i := 42
   j := 42
   k := 42)
+
+#eval fmt `(calc
+  1 = 1 := rfl
+  1 = 1 := rfl)

tests/lean/formatTerm.lean.expected.out

@@ -67,3 +67,6 @@ def foo✝ : a✝ b✝ c✝ d✝ e✝ f✝ g✝ a✝ b✝ c✝ d✝ e✝ f✝ g
   i✝ := 42
   j✝ := 42
   k✝ := 42
+calc
+  1 = 1 := rfl✝
+  1 = 1 := rfl✝