simulator: Add -h option for usag eand detect bad options

Add a `-h` option showing simulator usage

Detect incorrect option and when this happens, show usage.

Signed-off-by: Christophe de Dinechin <christophe@dinechin.org>

Author: c3d

SIMULATOR.md

@@ -27,25 +27,26 @@ The simulator can be started with the command-line options listed in the table b
 
 | Option | Description |
 | --- | --- |
+| -D[[`<whitespace>`]`<argument>`] | Set the pattern of recorder traces to show when a test fails. |
+| -E[[`<whitespace>`]`<argument>`] | Like `-e`, but also prints every stack level after each command (bottom of stack first). With the normal GUI, output goes to stderr; with `-H`, to stdout. The option may be repeated. |
+| -H | Headless mode: do not show a window, and exit when startup commands finish. Use with `-E` for batch scripting. On Linux, uses the offscreen Qt platform; on macOS, the native platform with a hidden window. |
+| -I | Initialize the user's environment. WARNING: This may overwrite user configuration with defaults. |
+| -K | Simulate typing of individual keys during tests. |
+| -N | Disable beeps. Use this if you get error messages about audio drivers. |
+| -O[`<test>` \| all] | Only configure test-suite recorder traces (`est_<test>` or `est_.*` for `all`) without enabling automatic test execution. |
+| -T[`<test>` \| all] | Run tests. Without a suffix, run the full test suite. With a suffix, select individual test suites. For example `-Tmatrices` will run the `matrices` portion of the test suite. |
 | -d[[`<whitespace>`]`<integer>`] | Set key delay time in milliseconds to slow down tests. Default = 0 ms. |
+| -e[[`<whitespace>`]`<argument>`] | Evaluate an RPL command line at startup, as if typed on the command line and executed with Enter. The option may be repeated to run several commands in order. |
+| -h | Show command-line usage and exit. |
 | -i[[`<whitespace>`]`<integer>`] | Set the maximum time waiting for an image to match the expected image during testing. Default = 500 ms. |
 | -k[[`<whitespace>`]`<argument>`] | Load a saved keymap to change keyboard layout. |
-| -K | Simulate typing of individual keys during tests. |
+| -l | With `-E`, prefix each printed stack line with its level number (`1:` is the top of stack). Default is to print values only. |
 | -m[[`<whitespace>`]`<integer>`] | Set the memory size available to the calculator in kilobytes. |
 | -n | Enable beeps while running the test suite (noisy testing). |
 | -r[[`<whitespace>`]`<integer>`] | Set the time to wait for a screen update in milliseconds. Default = 20 ms. |
 | -s[[`<whitespace>`]`<real>`] | Scale the application window by the given floating-point scaling factor. |
 | -t`<trace>` | Enable the named recorder trace. Multiple traces can be enabled by using multiple `-t` options, or by using a regular expression as an argument to `-t`. |
 | -w[[`<whitespace>`]`<integer>`] | Set the default time the test suite waits for a command to complete, in milliseconds. You can increase this to run the test suite on a very slow machine. The default = 1000 ms. |
-| -D[[`<whitespace>`]`<argument>`] | Set the pattern of recorder traces to show when a test fails. |
-| -e[[`<whitespace>`]`<argument>`] | Evaluate an RPL command line at startup, as if typed on the command line and executed with Enter. The option may be repeated to run several commands in order. |
-| -E[[`<whitespace>`]`<argument>`] | Like `-e`, but also prints every stack level after each command (bottom of stack first). With the normal GUI, output goes to stderr; with `-H`, to stdout. The option may be repeated. |
-| -H | Headless mode: use the offscreen Qt platform, do not show a window, and exit when startup commands finish. Use with `-E` for batch scripting. Implies `QT_QPA_PLATFORM=offscreen`. |
-| -l | With `-E`, prefix each printed stack line with its level number (`1:` is the top of stack). Default is to print values only. |
-| -I | Initialize the user's environment. WARNING: This may overwrite user configuration with defaults. |
-| -N | Disable beeps. Use this if you get error messages about audio drivers. |
-| -T[`<test>` \| all] | Run tests. Without a suffix, run the full test suite. With a suffix, select individual test suites. For example `-Tmatrices` will run the `matrices` portion of the test suite. |
-| -O[`<test>` \| all] | Only configure test-suite recorder traces (`est_<test>` or `est_.*` for `all`) without enabling automatic test execution. |
 
 
 ## Arguments