TODO: fix TODOs (a recursive TODO tale)

[Jutho]

Some TODOs should definitely not be forgotten before we reach version 1, e.g.

• https://github.com/Jutho/TensorKit.jl/blob/master/src/tensors/diagonal.jl#L55
• https://github.com/Jutho/TensorKit.jl/blob/master/src/tensors/diagonal.jl#L113
• https://github.com/Jutho/TensorKit.jl/blob/master/src/tensors/diagonal.jl#L123
• https://github.com/Jutho/TensorKit.jl/blob/master/src/tensors/diagonal.jl#L266
• https://github.com/Jutho/TensorKit.jl/blob/master/src/tensors/diagonal.jl#L272
• https://github.com/Jutho/TensorKit.jl/blob/master/src/tensors/diagonal.jl#L276
• https://github.com/Jutho/TensorKit.jl/blob/master/src/auxiliary/linalg.jl#L52
• https://github.com/Jutho/TensorKit.jl/blob/master/src/auxiliary/linalg.jl#L55
• https://github.com/Jutho/TensorKit.jl/blob/master/src/auxiliary/linalg.jl#L77
• https://github.com/Jutho/TensorKit.jl/blob/master/src/auxiliary/linalg.jl#L157
• https://github.com/Jutho/TensorKit.jl/blob/master/src/auxiliary/linalg.jl#L190
• https://github.com/Jutho/TensorKit.jl/blob/master/src/auxiliary/linalg.jl#L219
• https://github.com/Jutho/TensorKit.jl/blob/master/src/auxiliary/linalg.jl#L225
• https://github.com/Jutho/TensorKit.jl/blob/master/src/auxiliary/linalg.jl#L228
• https://github.com/Jutho/TensorKit.jl/blob/master/src/auxiliary/linalg.jl#L341
• https://github.com/Jutho/TensorKit.jl/blob/master/src/tensors/vectorinterface.jl#L66
• https://github.com/Jutho/TensorKit.jl/blob/master/src/tensors/vectorinterface.jl#L126
• https://github.com/Jutho/TensorKit.jl/blob/master/ext/TensorKitFiniteDifferencesExt.jl#L28
• https://github.com/Jutho/TensorKit.jl/blob/master/docs/src/lib/tensors.md#L230
• https://github.com/Jutho/TensorKit.jl/blob/master/src/tensors/abstracttensor.jl#L234
• https://github.com/Jutho/TensorKit.jl/blob/master/src/tensors/abstracttensor.jl#L316
• https://github.com/Jutho/TensorKit.jl/blob/master/src/tensors/abstracttensor.jl#L345
• https://github.com/Jutho/TensorKit.jl/blob/master/src/tensors/tensoroperations.jl#L185
• https://github.com/Jutho/TensorKit.jl/blob/master/src/tensors/tensoroperations.jl#L222
• https://github.com/Jutho/TensorKit.jl/blob/master/src/tensors/tensoroperations.jl#L293
• https://github.com/Jutho/TensorKit.jl/blob/master/src/tensors/tensoroperations.jl#L338
• https://github.com/Jutho/TensorKit.jl/blob/master/src/planar/postprocessors.jl#L54
• https://github.com/Jutho/TensorKit.jl/blob/master/src/spaces/gradedspace.jl#L137
• https://github.com/Jutho/TensorKit.jl/blob/master/src/spaces/gradedspace.jl#L267
• https://github.com/Jutho/TensorKit.jl/blob/master/src/tensors/braidingtensor.jl#L57
• https://github.com/Jutho/TensorKit.jl/blob/master/src/tensors/braidingtensor.jl#L110
• https://github.com/Jutho/TensorKit.jl/blob/master/src/tensors/braidingtensor.jl#L172
• https://github.com/Jutho/TensorKit.jl/blob/master/src/tensors/braidingtensor.jl#L183
• https://github.com/Jutho/TensorKit.jl/blob/master/src/tensors/indexmanipulations.jl#L158
• https://github.com/Jutho/TensorKit.jl/blob/master/src/tensors/indexmanipulations.jl#L373
• https://github.com/Jutho/TensorKit.jl/blob/master/src/tensors/indexmanipulations.jl#L418
• https://github.com/Jutho/TensorKit.jl/blob/master/src/tensors/indexmanipulations.jl#L484
• https://github.com/Jutho/TensorKit.jl/blob/master/src/tensors/indexmanipulations.jl#L511
• https://github.com/Jutho/TensorKit.jl/blob/master/src/tensors/indexmanipulations.jl#L607
• https://github.com/Jutho/TensorKit.jl/blob/master/src/fusiontrees/iterator.jl#L27
• https://github.com/Jutho/TensorKit.jl/blob/master/src/fusiontrees/fusiontrees.jl#L202
• https://github.com/Jutho/TensorKit.jl/blob/master/docs/src/man/tensors.md#L1261
• https://github.com/Jutho/TensorKit.jl/blob/master/docs/src/man/tensors.md#L1265
• https://github.com/Jutho/TensorKit.jl/blob/master/docs/src/man/sectors.md#L1255
• https://github.com/Jutho/TensorKit.jl/blob/master/src/tensors/linalg.jl#L167
• https://github.com/Jutho/TensorKit.jl/blob/master/src/tensors/linalg.jl#L181
• https://github.com/Jutho/TensorKit.jl/blob/master/src/tensors/linalg.jl#L233
• https://github.com/Jutho/TensorKit.jl/blob/master/src/tensors/linalg.jl#L328
• https://github.com/Jutho/TensorKit.jl/blob/master/src/tensors/linalg.jl#L347
• https://github.com/Jutho/TensorKit.jl/blob/master/ext/TensorKitChainRulesCoreExt/tensoroperations.jl#L22
• https://github.com/Jutho/TensorKit.jl/blob/master/ext/TensorKitChainRulesCoreExt/tensoroperations.jl#L93
• https://github.com/Jutho/TensorKit.jl/blob/master/ext/TensorKitChainRulesCoreExt/tensoroperations.jl#L134
• https://github.com/Jutho/TensorKit.jl/blob/master/ext/TensorKitChainRulesCoreExt/linalg.jl#L34
• https://github.com/Jutho/TensorKit.jl/blob/master/test/runtests.jl#L62
• https://github.com/Jutho/TensorKit.jl/blob/master/test/braidingtensor.jl#L1

[Jutho]

That's a scary long list