Fix some typos in doc comments

stdlib/public/Concurrency/Executor.swift

@@ -93,7 +93,7 @@ public protocol SchedulingExecutor: Executor {
   ///              will not be executed before this time.
   /// - tolerance: The maximum additional delay permissible before the
   ///              job is executed.  `nil` means no limit.
-  /// - clock:     The clock used for the delay..
+  /// - clock:     The clock used for the delay.
   @available(StdlibDeploymentTarget 6.2, *)
   func enqueue<C: Clock>(_ job: consuming ExecutorJob,
                          at instant: C.Instant,

stdlib/public/Concurrency/Task+PriorityEscalation.swift

@@ -94,7 +94,7 @@ extension UnsafeCurrentTask {
 /// The handler will only trigger if a priority escalation occurs while the
 /// operation is in progress.
 ///
-/// If multiple task escalation handlers are nester they will all be triggered.
+/// If multiple task escalation handlers are nested they will all be triggered.
 ///
 /// Task escalation propagates through structured concurrency child-tasks.
 ///

stdlib/public/Observation/Sources/Observation/Locking.swift

@@ -9,10 +9,10 @@
 //
 //===----------------------------------------------------------------------===//
 
-// NOTE: this cant use Synchronization because it is deployed before that was
+// NOTE: this can't use Synchronization because it is deployed before that was
 // introduced and availability wont let it be hidden behind an internal type.
 // The Swift internal runtime locking cannot be used since that emits dependent
-// symbols that are not provided by this library - so instead it has to re-implement 
+// symbols that are not provided by this library - so instead it has to re-implement
 // all of this on its own... 
 
 #if canImport(Darwin.os.lock)

stdlib/public/Observation/Sources/Observation/ObservationRegistrar.swift

@@ -217,7 +217,7 @@ public struct ObservationRegistrar: Sendable {
   ///
   /// You don't need to create an instance of
   /// ``Observation/ObservationRegistrar`` when using the
-  /// ``Observation/Observable()`` macro to indicate observably
+  /// ``Observation/Observable()`` macro to indicate observability
   /// of a type.
   public init() {
   }

stdlib/public/core/EmbeddedRuntime.swift

@@ -48,7 +48,7 @@ public struct ClassMetadata {
   └──────────────┴──────────────────────────────────────────────┘
 
   If the highest bit (doNotFreeBit) is set, the behavior of dropping the last reference (release operation where
-  refcount ends up being 0) is altered to avoid calling free() on the object (deinit is still run). This is crutial for
+  refcount ends up being 0) is altered to avoid calling free() on the object (deinit is still run). This is crucial for
   class instances that are promoted by the compiler from being heap-allocated to instead be located on the stack
   (see swift_initStackObject).