fix comment

Author: majocha

src/Compiler/Utilities/lib.fs

@@ -466,7 +466,7 @@ module WeakMap =
     /// is strongly referenced elsewhere (backed by ConditionalWeakTable).
     ///
     /// Usage:
-    ///   let getValueFor = WeakMap.getOrCreate (fun () -> expensiveInit())
+    ///   let getValueFor = WeakMap.getOrCreate (fun key -> expensiveInit key)
     ///   let v = getValueFor someKey
     let getOrCreate valueFactory =
         let table = ConditionalWeakTable<_, _>()

src/Compiler/Utilities/lib.fsi

@@ -297,9 +297,13 @@ module Async =
     val map: ('T -> 'U) -> Async<'T> -> Async<'U>
 
 module internal WeakMap =
-    /// Attach a value to arbitrary keys using a ConditionalWeakTable.
-    /// Each distinct key gets its own value produced by createValue().
-    /// The value is lazily created and stays alive only as long as the key is strongly referenced elsewhere.
+    /// Provides association of lazily-created values with arbitrary key objects.
+    /// The associated value is created on first request and kept alive only while the key
+    /// is strongly referenced elsewhere (backed by ConditionalWeakTable).
+    ///
+    /// Usage:
+    ///   let getValueFor = WeakMap.getOrCreate (fun key -> expensiveInit key)
+    ///   let v = getValueFor someKey
     val internal getOrCreate:
         valueFactory: ('Key -> 'Value) -> ('Key -> 'Value)
             when 'Key: not struct and 'Key: not null and 'Value: not struct