Corrected order of matrix multiplication for cm operator.

[peterwilliams97]

The change to Matrix.Concat made for this fix simplified some text extraction matrix code.

[CLAassistant]

All committers have signed the CLA.

[codecov]

Codecov Report

Merging #328 into v3 will increase coverage by <.01%.
The diff coverage is 62.5%.

@@            Coverage Diff             @@
##               v3     #328      +/-   ##
==========================================
+ Coverage   38.68%   38.69%   +<.01%     
==========================================
  Files         122      122              
  Lines       23083    23083              
==========================================
+ Hits         8930     8931       +1     
  Misses      12872    12872              
+ Partials     1281     1280       -1

Impacted Files	Coverage Δ
pdf/internal/transform/matrix.go	27.27% <0%> (+1.81%)	⬆️
pdf/extractor/text.go	61.27% <100%> (ø)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update caca4b4...4d2d4ea. Read the comment docs.