[clang] [clang][docs] Modernize attribute docs for darwin specifics (PR #88448)

[Steven Wu via cfe-commits]

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@@ -1604,23 +1604,31 @@ specifies availability for the current target platform, the availability
 attributes are ignored. Supported platforms are:
 
 ``ios``
-  Apple's iOS operating system. The minimum deployment target is specified by
-  the ``-mios-version-min=*version*`` or ``-miphoneos-version-min=*version*``
-  command-line arguments.
+  Apple's iOS operating system. The minimum deployment target is specified 
+  as part of the triple. Alternatively, it can be specified by the 
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cachemeifyoucan wrote:

Maybe be a bit more specific and reference `-target` driver option?

https://github.com/llvm/llvm-project/pull/88448