Create a script to collect all bufmod TODOs

[doriable]

This is a script for collecting all TODOs on bufmod that are
not on main. Sample output:

private/bufpkg/bufmodule/remote_dep.go: 44 // TODO: This needs a LOT of testing.
private/pkg/connectclient/connectclient.go: 21 // TODO: eliminate config, just make the below MakeOptions, add httpClient as a parameter to Make
private/pkg/dag/graph.go: 45 // TODO: It really stinks that we have to use the constructor. We have what amounts
private/pkg/slicesext/slicesext.go: 146 // TODO: Delete this in favor of slices.Clone.
private/pkg/slicesext/slicesext.go: 166 // TODO: Make ToStructMap use this logic, remove ToStructMapOmitEmpty, to match other functions.
private/pkg/slicesext/slicesext.go: 315 // TODO: Replace with slices.Sort when we only support Go versions >= 1.21.
private/pkg/syncext/syncext.go: 25 // TODO: This is directly copied from 1.21 source, remove when no longer need <1.20.
private/pkg/syncext/syncext.go: 57 // TODO: This is directly copied from 1.21 source, remove when no longer need <1.20.

[doriable]

@bufdev I wasn't sure if we wanted to put this as a part of make generate, I didn't want to inadvertently cause CI issues by doing that. It seems reasonable to generate and/use on an ad-hoc basis for now but yeah, let me know what you think.

[bufdev]

This script still has bugs, example:

586:					// TODO: sweep and check paths gone: 593 // TODO: add default values
586:					// TODO: sweep and check paths gone: 773 // TODO in v2