Ensure return statements are on a line of their own

[fingolfin]

This allows us to see in code coverage reports which of those returns are actually being taken.

[codecov[bot]]

Codecov Report

Merging #230 (5e1a19b) into master (89b3283) will decrease coverage by 0.20%. The diff coverage is 63.88%.

@@            Coverage Diff             @@
##           master     #230      +/-   ##
==========================================
- Coverage   78.71%   78.51%   -0.21%     
==========================================
  Files          37       37              
  Lines       17172    17364     +192     
==========================================
+ Hits        13517    13633     +116     
- Misses       3655     3731      +76     

Impacted Files	Coverage Δ
gap/base/recognition.gi	71.79% <0.00%> (-0.98%)	:arrow_down:
gap/matrix/slconstr.gi	5.90% <0.00%> (-0.01%)	:arrow_down:
gap/tools.gi	28.57% <0.00%> (-4.16%)	:arrow_down:
gap/perm/largebase.gi	81.60% <46.66%> (-1.66%)	:arrow_down:
gap/projective/findnormal.gi	78.10% <53.33%> (-0.86%)	:arrow_down:
gap/projective/almostsimple.gi	74.18% <55.55%> (-0.17%)	:arrow_down:
gap/projective/classicalnatural.gi	92.49% <61.11%> (-0.72%)	:arrow_down:
gap/matrix/ppd.gi	93.27% <66.66%> (-0.74%)	:arrow_down:
gap/projective/AnSnOnFDPM.gi	81.28% <66.66%> (-0.08%)	:arrow_down:
gap/projective/tensor.gi	55.34% <66.66%> (-0.06%)	:arrow_down:
... and 7 more