[clang] [rtsan][NFC] Add documentation link to Function Effects (PR #113979)

[Florian Mayer via cfe-commits]

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@@ -11,11 +11,16 @@ RealtimeSanitizer (a.k.a. RTSan) is a real-time safety testing tool for C and C+
 projects. RTSan can be used to detect real-time violations, i.e. calls to methods
 that are not safe for use in functions with deterministic run time requirements.
 RTSan considers any function marked with the ``[[clang::nonblocking]]`` attribute
-to be a real-time function. If RTSan detects a call to ``malloc``, ``free``,
-``pthread_mutex_lock``, or anything else that could have a non-deterministic
-execution time in a function marked ``[[clang::nonblocking]]``
+to be a real-time function. At run-time, if RTSan detects a call to ``malloc``, 
+``free``, ``pthread_mutex_lock``, or anything else that could have a 
+non-deterministic execution time in a function marked ``[[clang::nonblocking]]``
----------------
fmayer wrote:

> or anything else that could have a non-deterministic execution time

that sounds like a guarantee. Isn't it more things that we _know_ to have a non-deterministic runtime

https://github.com/llvm/llvm-project/pull/113979