fix error in reserve_exact docstring

common/src/zalgo_string.rs

@@ -430,7 +430,7 @@ impl ZalgoString {
     /// Same as [`String::reserve_exact`].
     ///
     /// Unlike [`reserve`](ZalgoString::reserve), this will not deliberately over-allocate to speculatively avoid frequent allocations.
-    /// After calling `reserve_exact`, capacity will be equal to `self.len() + additional`.
+    /// After calling `reserve_exact`, capacity will be equal to or greater than `self.len() + additional`.
     ///
     /// Does nothing if the capacity is already sufficient.
     ///