[LLD] lld does not add the entry size for the `.plt` and `.plt.sec` sections.

```c
// main.c
#include

int main() {
puts("hello\n");
printf("hello\n");
return 0;
}
```

lld output of the .plt section

from `llvm-readobj --sections main`
lld output compiled with `clang main.c -fuse-ld=lld -o main`
```sh
Section {
Index: 17
Name: .plt (161)
Type: SHT_PROGBITS (0x1)
Flags [ (0x6)
SHF_ALLOC (0x2)
SHF_EXECINSTR (0x4)
]
Address: 0x17E0
Offset: 0x7E0
Size: 64
Link: 0
Info: 0
AddressAlignment: 16
EntrySize: 0
}
```

bfd output compiled with `clang main.c -fuse-ld=bfd -o main`

```sh
Section {
Index: 10
Name: .plt (104)
Type: SHT_PROGBITS (0x1)
Flags [ (0x6)
SHF_ALLOC (0x2)
SHF_EXECINSTR (0x4)
]
Address: 0x1020
Offset: 0x1020
Size: 48
Link: 0
Info: 0
AddressAlignment: 16
EntrySize: 16
}
```

Reproduce the report with the shown main.c example using clang -fuse-ld=lld, then inspect the .plt and .plt.sec section headers with llvm-readobj. Compare the reported EntrySize and section layout with the bfd output. Done means lld reports the appropriate entry size for these sections, with coverage for the observed behavior.

Written by the indexing model from the issue text.