[now-cli] Render correct command for now ls $path_alias_url

[TooTallNate]

Previously, if you ran now ls with a URL for a path alias, then an error message Cannot read property 'replace' of undefined would occur.

Now, a message is logged saying to instead run now alias ls $url which is the correct command to get path rules relevant to a path alias URL.

$ now ls rules.domain.com
> Found matching path alias: rules.domain.com
> Please run `now alias ls rules.domain.com` instead

Fixes #2987.

[styfle]

@TooTallNate Is it possible to add a test for this behavior?

[codecov-io]

Codecov Report

Merging #2988 into canary will decrease coverage by 2.04%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           canary    #2988      +/-   ##
==========================================
- Coverage   13.37%   11.33%   -2.05%     
==========================================
  Files         268      268              
  Lines       10344    10096     -248     
  Branches     1218     1306      +88     
==========================================
- Hits         1384     1144     -240     
+ Misses       8898     8862      -36     
- Partials       62       90      +28

Impacted Files	Coverage Δ
src/util/output/create-output.ts	31.25% <0%> (-12.34%)	⬇️
src/util/dev/server.ts	61.21% <0%> (-5.69%)	⬇️
src/util/prefer-v2-deployment.ts	56.25% <0%> (-5.66%)	⬇️
src/util/dev/yarn-installer.ts	85.71% <0%> (-5.03%)	⬇️
src/util/dev/builder.ts	73.07% <0%> (-4.35%)	⬇️
src/util/get-files.ts	87.77% <0%> (-3.89%)	⬇️
src/util/projects/get-project-by-id-or-name.ts	25% <0%> (-3.58%)	⬇️
src/util/dev/builder-cache.ts	77.27% <0%> (-3.48%)	⬇️
src/commands/list.js	0% <0%> (ø)	⬆️
src/util/metrics.ts	70.58% <0%> (+2.4%)	⬆️

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