the `isone` predicate throws instead of returning `false`

[nsajko]

julia> using FixedPointNumbers

julia> isone(0.0Q0f15)
ERROR: ArgumentError: Q0f15 is a 16-bit type representing 65536 values from -1.0 to 0.99997; cannot represent 1
Stacktrace:
 [1] throw_converterror(::Type{Q0f15}, x::Int64)
   @ FixedPointNumbers ~/.julia/packages/FixedPointNumbers/Dn4hv/src/FixedPointNumbers.jl:326
 [2] rawone(::Type{Q0f15})
   @ FixedPointNumbers ~/.julia/packages/FixedPointNumbers/Dn4hv/src/fixed.jl:41
 [3] oneunit(::Type{Q0f15})
   @ FixedPointNumbers ~/.julia/packages/FixedPointNumbers/Dn4hv/src/FixedPointNumbers.jl:108
 [4] one(::Type{Q0f15})
   @ FixedPointNumbers ~/.julia/packages/FixedPointNumbers/Dn4hv/src/FixedPointNumbers.jl:109
 [5] one(x::Q0f15)
   @ FixedPointNumbers ~/.julia/packages/FixedPointNumbers/Dn4hv/src/FixedPointNumbers.jl:222
 [6] isone(x::Q0f15)
   @ Base ./number.jl:62
 [7] top-level scope
   @ REPL[2]:1

julia> versioninfo()
Julia Version 1.11.3
Commit d63adeda50d (2025-01-21 19:42 UTC)
Build Info:
  Official https://julialang.org/ release
Platform Info:
  OS: Linux (x86_64-linux-gnu)
  CPU: 8 × AMD Ryzen 3 5300U with Radeon Graphics
  WORD_SIZE: 64
  LLVM: libLLVM-16.0.6 (ORCJIT, znver2)
Threads: 1 default, 0 interactive, 1 GC (on 8 virtual cores)
Environment:
  JULIA_NUM_PRECOMPILE_TASKS = 4
  JULIA_PKG_PRECOMPILE_AUTO = 0

(@v1.11) pkg> st FixedPointNumbers
Status `~/.julia/environments/v1.11/Project.toml`
  [53c48c17] FixedPointNumbers v0.8.5