Fix flag names in @available docs.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@308048 91177308-0d34-0410-b5e6-96231b3b80d8

docs/LanguageExtensions.rst

@@ -1275,8 +1275,8 @@ Objective-C @available
 ----------------------
 
 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),