[slang] Introduce net aliases bits duplication checks

[likeamahoney]

Introduce 2 new net alias bit checks from SystemVerilog LRM section 10.11:

• check that net aliased to itself
• check that aliased bits specified more than once at module instance scope

[likeamahoney]

I think with it LRM section 10.11 is done

[codecov]

Codecov Report

Attention: Patch coverage is 86.30137% with 10 lines in your changes missing coverage. Please review.

Project coverage is 94.68%. Comparing base (4dee9aa) to head (16b72d5).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1045      +/-   ##
==========================================
- Coverage   94.71%   94.68%   -0.03%     
==========================================
  Files         191      191              
  Lines       47664    47726      +62     
==========================================
+ Hits        45144    45190      +46     
- Misses       2520     2536      +16     

Files	Coverage Δ
include/slang/ast/Compilation.h	100.00% <100.00%> (ø)
include/slang/ast/Scope.h	100.00% <ø> (ø)
include/slang/ast/symbols/InstanceSymbols.h	100.00% <100.00%> (ø)
source/ast/symbols/InstanceSymbols.cpp	94.51% <100.00%> (+<0.01%)	⬆️
source/ast/symbols/MemberSymbols.cpp	96.86% <85.71%> (-0.61%)	⬇️

... and 1 file with indirect coverage changes

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