Decl macro parser reaching end of input reports as "found `<eof>`" which could be more descriptive

Code

macro_rules! item {
    ($item:item) => {$item}
}
item!(mod x);

Current output

error: expected one of `;` or `{`, found `<eof>`
 --> src/lib.rs:4:11
  |
2 |     ($item:item) => {$item}
  |      ---------- while parsing argument for this `item` macro fragment
3 | }
4 | item!(mod x);
  |           ^ expected one of `;` or `{`

error: could not compile `playground` (lib) due to 1 previous error

Desired output

error: expected one of `;` or `{`, found end of macro input
 --> src/lib.rs:4:11
  |
2 |     ($item:item) => {$item}
  |      ---------- while parsing argument for this `item` macro fragment
3 | }
4 | item!(mod x);
  |            ^ expected one of `;` or `{`

error: could not compile `playground` (lib) due to 1 previous error

Rationale and extra context

<eof> doesn't necessarily tell people much. I imagine there might be newcomers who have no idea what this acronym is supposed to mean without googling it, it's also just an odd assortment of characters with the <> going on so I think we can improve on that :) Ideally it would also point to after the last token, since that last token was parsed correctly, though I guess that is difficult for implementation reasons.

In fact I just noticed we do the same outside of macros, that is a bare mod x in a file triggers the same so that might be good to adjust as well with a found end of file instead.

Other cases

No response

Rust Version

rustc 1.79.0-nightly (805813650 2024-03-31)
binary: rustc
commit-hash: 805813650248c1a2f6f271460d728d1bb852d2a7
commit-date: 2024-03-31
host: x86_64-pc-windows-msvc
release: 1.79.0-nightly
LLVM version: 18.1.2

Anything else?

No response

Start by reproducing the macro example and the bare mod x case from the issue with the listed Rust version, then trace where the parser formats an unexpected EOF. Compare both diagnostics with the desired wording and span behavior. Done means EOF is described as the end of macro input or file rather than \u003ceof\u003e, with regression coverage for the affected cases.