docs: improve comments on replace_func_by_id

Signed-off-by: Victor Adossi <vadossi@cosmonic.com>

src/module/functions/mod.rs

@@ -445,11 +445,12 @@ impl Module {
             .context("module does not export a memory")
     }
 
-    /// Replace a single function with the result of the provided builder function.
+    /// Replace a single function that is either an import or an export
+    /// with the result of the provided builder function.
     ///
     /// When called, if `builder` produces a None value, the function in question will be
     /// replaced with a stub that does nothing (more precisely, a function with an unreachable body).
-    pub fn replace_fn_by_id<F>(&mut self, fid: FunctionId, fn_builder: F) -> Result<()>
+    pub fn replace_func_by_id<F>(&mut self, fid: FunctionId, fn_builder: F) -> Result<()>
     where
         F: FnOnce((&FuncParams, &FuncResults)) -> Result<Option<LocalFunction>>,
     {