langref: fixes incorrect description of cmpxchg functions

Author: ityonemo

doc/langref.html.in

@@ -4536,7 +4536,7 @@ comptime {
       <pre>{#syntax#}@cmpxchgStrong(comptime T: type, ptr: *T, expected_value: T, new_value: T, success_order: AtomicOrder, fail_order: AtomicOrder) ?T{#endsyntax#}</pre>
       <p>
       This function performs a strong atomic compare-and-exchange operation, returning {#syntax#}null{#endsyntax#}
-      if the current value is not the given expected value. It's the equivalent of this code,
+      if the current value is the given expected value. It's the equivalent of this code,
       except atomic:
       </p>
       {#code|not_atomic_cmpxchgStrong.zig#}
@@ -4558,7 +4558,7 @@ comptime {
       <pre>{#syntax#}@cmpxchgWeak(comptime T: type, ptr: *T, expected_value: T, new_value: T, success_order: AtomicOrder, fail_order: AtomicOrder) ?T{#endsyntax#}</pre>
       <p>
       This function performs a weak atomic compare-and-exchange operation, returning {#syntax#}null{#endsyntax#}
-      if the current value is not the given expected value. It's the equivalent of this code,
+      if the current value is the given expected value. It's the equivalent of this code,
       except atomic:
       </p>
       {#syntax_block|zig|cmpxchgWeakButNotAtomic#}