Support printing weeks and quarters

[LilithHafner]

Before

julia> string(AnchoredInterval{Week(1)}(floor(today(), Week)))
ERROR: MethodError: no method matching prefix(::Type{Week})
Closest candidates are:
  prefix(::Period) at ~/.julia/dev/Intervals/src/description.jl:58
  prefix(::Type{Year}) at ~/.julia/dev/Intervals/src/description.jl:62
  prefix(::Type{Month}) at ~/.julia/dev/Intervals/src/description.jl:63
  ...
Stacktrace:
 [1] prefix(p::Week)
   @ Intervals ~/.julia/dev/Intervals/src/description.jl:59
 [2] description(dt::Date, p::Week, suffix::String)
   @ Intervals ~/.julia/dev/Intervals/src/description.jl:22
 [3] description(interval::AnchoredInterval{Week(1), Date, Closed, Open}, s::String)
   @ Intervals ~/.julia/dev/Intervals/src/description.jl:4
 [4] description(i::AnchoredInterval{Week(1), Date, Closed, Open})
   @ Intervals ~/.julia/dev/Intervals/src/description.jl:1
 [5] print(io::IOBuffer, interval::AnchoredInterval{Week(1), Date, Closed, Open})
   @ Intervals ~/.julia/dev/Intervals/src/anchoredinterval.jl:256
 [6] print_to_string(xs::AnchoredInterval{Week(1), Date, Closed, Open})
   @ Base ./strings/io.jl:144
 [7] string(xs::AnchoredInterval{Week(1), Date, Closed, Open})
   @ Base ./strings/io.jl:185
 [8] top-level scope
   @ REPL[26]:1

After

julia> string(AnchoredInterval{Week(1)}(floor(today(), Week)))
"[WB 2022-06-06)"

[codecov]

Codecov Report

Merging #194 (b4b1994) into master (cb4f4d5) will decrease coverage by 0.26%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master     #194      +/-   ##
==========================================
- Coverage   81.73%   81.46%   -0.27%     
==========================================
  Files          11       11              
  Lines         624      626       +2     
==========================================
  Hits          510      510              
- Misses        114      116       +2     

Impacted Files	Coverage Δ
src/description.jl	94.87% <0.00%> (-5.13%)	⬇️

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[LilithHafner]

Duplicate of #164