XLS is detected as `application/x-ole-storage`, not `application/vnd.ms-excel`

[justanotheranonymoususer]

Hi, there are 2 problems here:

XLS file not being detected by cfb dependency, because it can't handle the partial buffer of 8192 bytes. open here:

infer/src/matchers/doc.rs

Line 112 in 81e537f

if let Ok(file) = cfb::CompoundFile::open(Cursor::new(buf)) {

returns:

kind: InvalidData, error: "Malformed FAT (FAT has 66 entries, but file has only 15 sectors)"

Not sure what's the best solution here, in this doc I found they suggest to look at offset 512 to determine the doc type such as doc/xls/ppt:
https://sceweb.sce.uhcl.edu/abeysekera/itec3831/labs/FILE%20SIGNATURES%20TABLE.pdf

Second problem is that it falls back to MSI, but it has nothing to do with MSI or installers, so perhaps MSI should have a stricter check.

CreditCard.zip

[justanotheranonymoususer]

Here's a working implementation if you want to borrow it:
https://github.com/mmalecot/file-format/blob/bb09c0f71415a22909ae41fa6bc6521b06367375/src/readers.rs#L171