Set --help usage line to match node client (#149)

Signed-off-by: Matthew Peveler <matt.peveler@gmail.com>

Author: MasterOdin

tldr.py

@@ -345,8 +345,7 @@ def update_cache(language=None):
 def main():
     parser = ArgumentParser(
         prog="tldr",
-        usage="tldr [-u] [-p PLATFORM] [-l] [-s SOURCE] [-c] [-r] [-L LANGUAGE]" +
-        " command",
+        usage="tldr command [options]",
         description="Python command line client for tldr"
     )
     parser.add_argument(