PMusrCanvas was the TCanvas based front end of musrview. Since the ROOT7
rewrite it is no longer part of the build, so drop the class, its header and its
LinkDef rather than leave dead code behind.
Also update the comments in PRunListCollection, PRunMuMinus, PRunSingleHisto
and musrt0 which still named the class, and repair the header comment of
PFourierCanvasLinkDef.h, which carried the file name of the LinkDef it had been
copied from.
Clean rebuild, tests 87/87.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01H6YiUNBTMDX9uA3Ts1w2nW
suter_aandClaude Opus 5
2cb76879ff