[docs] Update tracing docs with macOS instructions (#9284)

Documentation/guides/tracing.md

@@ -309,6 +309,13 @@ dotnet restore foo.csproj
 dotnet trace collect --format speedscope -- dotnet build -bl --no-restore foo.csproj
 ```
 
+On MacOS (and possibly linux) you need to pass `-p:UseSharedCompilation=false` otherwise the trace will hang.
+
+```dotnetcli
+dotnet restore foo.csproj
+dotnet trace collect --format speedscope -- dotnet build -bl --no-restore foo.csproj -p:UseSharedCompilation=false
+```
+
 This should result in `.speedscope` and `.nettrace` files in the
 current directory.
 
@@ -319,6 +326,13 @@ dotnet build foo.csproj
 dotnet trace collect --format speedscope -- dotnet build "-t:Run" -bl --no-restore foo.csproj
 ```
 
+On MacOS (and possibly linux) you need to pass `-p:UseSharedCompilation=false` otherwise the trace will hang.
+
+```dotnetcli
+dotnet restore foo.csproj
+dotnet trace collect --format speedscope -- dotnet build "-t:Run" -bl --no-restore foo.csproj -p:UseSharedCompilation=false
+```
+
 I found that `"` is necessary when `:` characters are present in the
 command. This appears to be some kind of argument parsing issue with
 `dotnet trace`.