j2objc command-line flags is missing some flags

[bstpierr]

Specifically, --generate-deprecated isn't mentioned, and I think a few others might be missing too looking at https://github.com/google/j2objc/blob/5a81abc43d2e2aeb530c91eb380232afaadf6469/translator/src/main/java/com/google/devtools/j2objc/Options.java

[tomball]

--generate-deprecated is there, but it's buried in the messy help message. I'm reorganizing that message today to make it easier to read, and removing a few obsolete flags. You're right, though, that -Xno-jsni-warnings wasn't included.

Usage: j2objc <options> <source files>
where possible options include:
-sourcepath <path>        Specify where to find input source files
-classpath <path>         Specify where to find user class files
-d <directory>            Specify where to place generated Objective-C files
-g                        Generate debugging support
--no-package-directories  Generate output files to specified directory, without
                            creating package sub-directories
-x <language>             Specify what language to output.  Possible values
                            are objective-c (default) and objective-c++
-use-reference-counting   Generate Objective-C code to support iOS manual
                            reference counting (default)
-use-gc                   Generate Objective-C code to support garbage
                            collection (requires libjre_emul.a rebuild)
-use-arc                  Generate Objective-C code to support Automatic
                            Reference Counting (ARC)
--build-closure           Translate dependent classes if out-of-date
-Werror                   Make all warnings into errors
-encoding <encoding>      Specify character encoding used by source files
-q, --quiet               Do not print status messages
-v, --verbose             Output messages about what the translator is doing
--prefix <package=prefix> Substitute a specified prefix for a package name
--prefixes <file>         Specify a properties file with prefix definitions
-pluginpath <path>        Specify where to find plugin class files
-pluginoptions <options>  Comma separated key=value pairs passed to all plugins
--mapping <file>          Add a method mapping file
--dead-code-report <file> Specify a ProGuard usage report for dead code elimination
--mem-debug               Generate code to display memory allocation graphs
--doc-comments            Translate Javadoc comments into Xcode-compatible comments
--generate-deprecated     Generate deprecated attributes for deprecated methods,
                            classes and interfaces.
...