Update help text

src/hyperfine/app.rs

@@ -143,7 +143,9 @@ fn build_app() -> App<'static, 'static> {
                     "Perform benchmark runs for each value in the comma-separated list VALUES. \
                      Replaces the string '{VAR}' in each command by the current parameter value\
                      .\n\nExample:  hyperfine -L compiler gcc,clang '{compiler} -O2 main.cpp'\n\n\
-                     This performs benchmarks for 'gcc -O2 main.cpp' and 'clang -O2 main.cpp'.",
+                     This performs benchmarks for 'gcc -O2 main.cpp' and 'clang -O2 main.cpp'.\n\n\
+                     The option can be specified multiple times to run benchmarks for all \
+                     possible parameter combinations.\n"
                 ),
         )
         .arg(