Fix flag names in @available docs.

llvm-svn: 308048
diff --git a/clang/docs/LanguageExtensions.rst b/clang/docs/LanguageExtensions.rst
index e120a88..78f987c 100644
--- a/clang/docs/LanguageExtensions.rst
+++ b/clang/docs/LanguageExtensions.rst
@@ -1275,8 +1275,8 @@
 ----------------------
 
 It is possible to use the newest SDK but still build a program that can run on
-older versions of macOS and iOS by passing ``-mmacosx-version-info=`` /
-``--miphoneos-version-min=``.
+older versions of macOS and iOS by passing ``-mmacosx-version-min=`` /
+``-miphoneos-version-min=``.
 
 Before LLVM 5.0, when calling a function that exists only in the OS that's
 newer than the target OS (as determined by the minimum deployment version),