fix a typo in case docs

src/primitive/defs.rs

@@ -2048,7 +2048,7 @@ primitive!(
  ([2], Try, Misc, ("try", '⍣')),
  /// Call a pattern matching case
  ///
- /// [case] is calls its function and prevents errors from escaping a single [try].
+ /// [case] calls its function and prevents errors from escaping a single [try].
  /// Its primary use is in pattern matching.
  /// Consider this function:
  /// ex: F ← ⍣(