Show available content even if parsing fails

[awaitlink]

If parsing fails:

• Show the raw/plaintext file content in the Raw tab.
  • Consequently, remove the "input" from the error message linked below.
• If it's due to the remainder not being empty, show at least what's been parsed successfully (with a notice that it's not complete).
  • Consequently, maybe remove the "output" from the error message linked below (although having access to the debug representation of it may be useful, maybe it should be shown in the Raw tab instead).
• If some of the files (in case of Signal iOS) parsed successfully while others didn't, show at least those that parsed successfully. Indicate that other files could not be parsed (per-file errors).
  • Indicate in UI which files were parsed and which weren't.
  • If only some filenames couldn't be parsed, still show the files that parsed successfully.

https://github.com/u32i64/readlogs/blob/6267b116ed5f3f6a6349f5c3d514ba8908c8984e/src/parsers/mod.rs#L82-L88

(Edit: the error format has changed and the "input"/"output" values aren't currently shown in any case. However, it may be useful to show "output" in the case mentioned above.)