feat: support moon generate

[lijunchen]

No description provided.

[peter-jerry-ye-code-review]

Based on the provided git diff output, here are three observations that could be potential issues or areas for improvement:

1. Misspelled Command in moon.test.ignore:

   • In the moon.test.ignore file, there is a reference to a command xcat which seems to be a typo or an unintended command. Typically, cat is used to display the contents of a file, but there is no standard command named xcat. This could lead to errors during testing.

   +  $ xcat src/lib/a.mbt

   Suggestion: Replace xcat with cat or the appropriate command to display the file contents.

2. Potential Issue with moon tool embed Command:

   • The run_embed_text and run_embed_bin functions in crates/moon/src/cli/tool/embed.rs generate comments that indicate the content is generated by moon tool embed --text and moon tool embed --binary. However, there is no clear indication of how these generated files are used or integrated into the build process. If these files are critical to the build process, ensuring they are correctly referenced elsewhere in the code is important.

   +let mut content = format!(
   +    "// Generated by `moon tool embed --text`{}, do not edit.\n\n\
   +    let {} : String =\n",

   Suggestion: Verify that the generated files are correctly referenced and used in the build process. Ensure there are no missing steps or references to these files elsewhere in the codebase.

3. Incomplete Documentation in README.md:

   • The README.md file in crates/moon/tests/test_cases/pre_build.in/ ends without a newline, which can cause issues with some text editors or tools that expect files to end with a newline.

   +# username/hello
   \ No newline at end of file

   Suggestion: Add a newline at the end of the README.md file to ensure compatibility with various tools and editors.

These observations are based on the provided git diff output and the context provided. Further inspection of the codebase and its intended functionality may reveal additional insights or require adjustments to these suggestions.