fix: show exact package name while prompting for installation

[jamesgeorge007]

What kind of change does this PR introduce?
bugfix

Did you add tests for your changes?
Nope

If relevant, did you update the documentation?
N/A

Summary

Currently, the package name that shows up while prompting for installation is the same as the argument supplied as part of process.argv. However, this would be misleading if the user supplies the alias or the loader/plugin command (generators).

webpack-cli/packages/webpack-cli/lib/webpack-cli.js

Lines 359 to 361 in 767fe6b

	pkg = await promptInstallation(pkg, () => {
	logger.error(`For using this command you need to install: '${green(commandName)}' package`);
	});

$ webpack loader

Before

After

Does this PR introduce a breaking change?
Nope

Other information
N/A

[codecov]

Codecov Report

Merging #2338 (66691e7) into master (767fe6b) will not change coverage.
The diff coverage is 0.00%.

@@           Coverage Diff           @@
##           master    #2338   +/-   ##
=======================================
  Coverage   68.19%   68.19%           
=======================================
  Files          51       51           
  Lines        2053     2053           
  Branches      506      506           
=======================================
  Hits         1400     1400           
  Misses        653      653           

Impacted Files	Coverage Δ
packages/webpack-cli/lib/webpack-cli.js	89.84% <0.00%> (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 767fe6b...66691e7. Read the comment docs.

[rishabh3112]

Left a suggestion.