Make types more accurate

[rafalp]

Superseds #884

[codecov[bot]]

Codecov Report

Merging #903 (6a0d46b) into master (db239eb) will decrease coverage by 0.03%. The diff coverage is 77.77%.

@@            Coverage Diff             @@
##           master     #903      +/-   ##
==========================================
- Coverage   98.35%   98.32%   -0.04%     
==========================================
  Files         100      100              
  Lines        6321     6323       +2     
==========================================
  Hits         6217     6217              
- Misses        104      106       +2     

Impacted Files	Coverage Δ
ariadne/contrib/tracing/opentracing.py	97.77% <ø> (-0.03%)	:arrow_down:
ariadne/extensions.py	100.00% <ø> (ø)
ariadne/graphql.py	87.68% <ø> (ø)
ariadne/scalars.py	100.00% <ø> (ø)
ariadne/types.py	92.72% <33.33%> (-3.50%)	:arrow_down:
ariadne/asgi/handlers/graphql_ws.py	98.69% <100.00%> (+<0.01%)	:arrow_up:
ariadne/contrib/federation/interfaces.py	100.00% <100.00%> (ø)
ariadne/contrib/federation/objects.py	100.00% <100.00%> (ø)
ariadne/contrib/federation/schema.py	100.00% <100.00%> (ø)
ariadne/executable_schema.py	100.00% <100.00%> (ø)

:mega: Codecov can now indicate which changes are the most critical in Pull Requests. Learn more