small type inference fix

[robamu]

I experimented with https://github.com/pftbest/msp430_svd today, and got this compile error:

svdtools on  master [$] is 📦 v0.4.5 via 🐍 v3.12.3 via 🦀 v1.85.0
❯ cargo check
    Checking svdtools v0.4.5 (/home/rmueller/Rust/svdtools)
error[E0282]: type annotations needed
   --> src/html/html_cli.rs:403:32
    |
403 |         (filling > u16::MAX as _)
    |                                ^ cannot infer type

For more information about this error, try `rustc --explain E0282`.
error: could not compile `svdtools` (lib) due to 1 previous error