Improve normalisation of inline aliases

[fredden]

This pull request

• Removes useless aliasing of the same version (1.2.3 as 1.2.3 --> 1.2.3).
• Ensures only a single space is used around the as keyword (1.4.5 as 1.2.3 --> 1.4.5 as 1.2.3). Previous to this change, only pairs of spaces were removed ( --> , --> ); this change now reduces all repeated spaces into a single space for consistency ( --> , --> ).
• Adds more tests to cover changes being made.
• Updates tests with more accurate name ('branch alias' --> 'inline alias'), and to match upstream documentation.

@localheinz - please feel free to squash-merge this or rebase / change commits as you see fit.

[codecov]

Codecov Report

Merging #889 (dc83275) into main (339991a) will increase coverage by 0.03%.
The diff coverage is 100.00%.

❗ Current head dc83275 differs from pull request most recent head 44ca02a. Consider uploading reports for the commit 44ca02a to get more accurate results

@@             Coverage Diff              @@
##               main     #889      +/-   ##
============================================
+ Coverage     97.49%   97.53%   +0.03%     
- Complexity      158      160       +2     
============================================
  Files            30       30              
  Lines           679      690      +11     
============================================
+ Hits            662      673      +11     
  Misses           17       17              

Impacted Files	Coverage Δ
...rc/Vendor/Composer/VersionConstraintNormalizer.php	97.61% <100.00%> (+0.22%)	⬆️

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[fredden]

For reference, I have seen both 1.2.3 as 1.2.3 and 1.4.5 as 1.2.3 in the wild. This typically comes about when a specific version constraint is in place in a dependency, and the current project wants a newer version of some package.

For example:

• Package A requires package B at version 1.2.3.
• Package B follows semantic versioning.
• Package B releases version 1.2.4 to fix some bug.
• Root package requires package A.
• Root package wants the bug-fix, so uses an inline alias: 1.2.4 as 1.2.3.
• Later, some other feature is released for package B, which the root package wants, so the inline alias is changed to 1.4.5 as 1.2.3.
• A new version of package A is released requiring version 1.4.5.
• Root package alias is mistakenly updated to be 1.4.5 as 1.4.5.

I can supply concrete packages and versions if required.

[localheinz]

Thank you, @fredden!