Remove explicit getindex methods with RealInfinity indices

[jishnub]

These should be unnecessary if RealInfinity may be converted to a valid index using to_index, as is done in Infinities.jl now.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 1 line in your changes missing coverage. Please review.

Project coverage is 0.00%. Comparing base (4f757e7) to head (410613e).
Report is 13 commits behind head on master.

Files with missing lines	Patch %	Lines
src/infarrays.jl	0.00%	1 Missing ⚠️

❗ There is a different number of reports uploaded between BASE (4f757e7) and HEAD (410613e). Click for more details.

HEAD has 6 uploads less than BASE

Flag	BASE (4f757e7)	HEAD (410613e)
	9	3

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #207       +/-   ##
==========================================
- Coverage   86.14%   0.00%   -86.15%     
==========================================
  Files           6      10        +4     
  Lines         758    1117      +359     
==========================================
- Hits          653       0      -653     
- Misses        105    1117     +1012     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.