Fix source code typos

[luzpaz]

Description

Leftover typos that alter source code directly. There are also some source comment fixes mixed in.

How Has This Been Tested?

n/a

Screenshots, that help to understand the changes(if applicable):

Checklist:

• A test for the new functionality was added.
• All tests run without failure.
• The new code complies with the TiGL style guide.
• New classes have been added to the Python interface.
• API changes were documented properly in tigl.h.

[codecov-commenter]

Codecov Report

Merging #925 (d89aa43) into master (ab8a7d3) will not change coverage.
The diff coverage is 100.00%.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #925   +/-   ##
=======================================
  Coverage   69.52%   69.52%           
=======================================
  Files         298      298           
  Lines       24974    24974           
=======================================
  Hits        17363    17363           
  Misses       7611     7611           

Impacted Files	Coverage Δ
src/geometry/CTiglBSplineApproxInterp.h	100.00% <ø> (ø)
src/geometry/CTiglBSplineAlgorithms.cpp	96.99% <100.00%> (ø)
src/geometry/CTiglBSplineApproxInterp.cpp	96.99% <100.00%> (ø)
src/geometry/CTiglInterpolatePointsWithKinks.cpp	100.00% <100.00%> (ø)
...rc/structural_elements/CCPACSFuselageWallSegment.h	33.33% <100.00%> (ø)
src/wing/CCPACSWing.cpp	76.87% <100.00%> (ø)

[joergbrech]

Thanks!