LspFold breaks on typst file using tinymist lsp

[jmdevin]

Steps to Reproduce

1. Using the (tinymist lsp), open the following file (it is only one line, no blank line after):

   # Heading

2. Do :LspFold
3. See this error:

   Error detected while processing function lsp#lsp#FoldDocument[12]..<SNR>56_FoldRange:
   line   23:
   E16: Invalid range: :2, 2fold

   I know that this probably counts as a tinymist bug as well, but I believe this plugin should check whether a range of lines exists before trying to fold it, that way it can be ignored or maybe a better error message can be displayed.

   Additional details

   Server setup

   g:LspAddServer(
   [
       {
           name: 'tinymist-typst-lsp',
           filetype: ['typ', 'typst',],
           path: $HOME .. '/bin/tinymist',
           initializationOptions: {
               'exportPdf': 'onType',
               'formatterMode': "typstyle",
           },
       },
   ]
   )

   Tinymist version

   Build Timestamp:     2024-08-26T16:22:10.986712173Z
   Build Git Describe:  v0.11.20
   Commit SHA:          1f9a42c2e863f6b1fe8624da796e47adf44a9a83
   Commit Date:         None
   Commit Branch:       None
   Cargo Target Triple: x86_64-unknown-linux-gnu
   Typst Version:       0.11.1

   Vim version

   9.1.0689

[yegappan]

Thanks for reporting the issue. This should be addressed by ce7ce83368439e146b20afe6f907076447d3eb0e.