symbol concatenation with binary +

[quentin]

Introduce concatenation of symbol values with binary + operator.
Syntactic convenience since cat(...) already exists.

[codecov]

Codecov Report

Merging #2431 (b891606) into master (2914f7b) will increase coverage by 0.15%.
Report is 16 commits behind head on master.
The diff coverage is 72.67%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2431      +/-   ##
==========================================
+ Coverage   77.75%   77.90%   +0.15%     
==========================================
  Files         474      479       +5     
  Lines       31164    31435     +271     
==========================================
+ Hits        24232    24491     +259     
- Misses       6932     6944      +12     

Files	Coverage Δ
src/FunctorOps.cpp	60.81% <ø> (ø)
src/ast/IterationCounter.cpp	100.00% <100.00%> (ø)
src/ast/QualifiedName.h	94.11% <ø> (ø)
src/ast/Relation.h	100.00% <100.00%> (ø)
src/ast/Term.h	75.00% <100.00%> (-15.00%)	⬇️
src/ast/analysis/PrecedenceGraph.cpp	42.85% <100.00%> (+7.72%)	⬆️
src/ast/analysis/typesystem/Type.h	50.00% <ø> (ø)
...ast/analysis/typesystem/TypeConstrainsAnalysis.cpp	99.39% <100.00%> (+0.01%)	⬆️
...c/ast/analysis/typesystem/TypeConstrainsAnalysis.h	100.00% <ø> (ø)
src/ast/transform/ComponentInstantiation.cpp	92.33% <100.00%> (+0.16%)	⬆️
... and 36 more

... and 6 files with indirect coverage changes

[julienhenry]

Good idea, thanks !