Merge pull request #6161 from ethereum/yulOptIsExperimental

State that yul optimizer is experimental.

docs/using-the-compiler.rst

@@ -211,6 +211,7 @@ Input Description
             "constantOptimizer": false,
             // The new Yul optimizer. Mostly operates on the code of ABIEncoderV2.
             // It can only be activated through the details here.
+            // This feature is still considered experimental.
             "yul": false,
             // Future tuning options, currently unused.
             "yulDetails": {}

solc/CommandLineInterface.cpp

@@ -616,7 +616,7 @@ Allowed options)",
 			"Set for how many contract runs to optimize."
 			"Lower values will optimize more for initial deployment cost, higher values will optimize more for high-frequency usage."
 		)
-		(g_strOptimizeYul.c_str(), "Enable Yul optimizer in Solidity, mostly for ABIEncoderV2.")
+		(g_strOptimizeYul.c_str(), "Enable Yul optimizer in Solidity, mostly for ABIEncoderV2. Still considered experimental.")
 		(g_argPrettyJson.c_str(), "Output JSON in pretty format. Currently it only works with the combined JSON output.")
 		(
 			g_argLibraries.c_str(),