Re-add support for revision hash or local/editing keyword as dependency description

[wcrd]

Description

Issue: #1666

This MR makes a small change to how the description property of the dependency vscode.TreeItem gets determined.

• For dependencies using a specific revision it will show the partial commit hash as the description
• For dependencies that are paths to a local pacakge is will show the local keyword
• For dependencies that are edited local versions of a dependency it will show the editing keyword

This is not 'new' functionality - v2.0.2 and earlier of this extension had this functionality.

Code Changes

• Updated the ResolvedDependency interface to additionally have the revision value
• Added getDescription function to PackageNode to get the correct description value based on the package type

Additionally I also slightly modified the new PackageNode.id property to utilise the partial commit hash if no version variable was available. Prior to this change, for the specific revision and local packages the id was showing as "{packageName}-". I can remove this if needed.

Testing

I did not add any tests for these changes. Existing suite passed locally. Based on the current suite I wasn't sure if this warranted additional tests - please lmk if I need to add some.

Tasks

• Required tests have been written
• Documentation has been updated
• Added an entry to CHANGELOG.md if applicable

[award999]

LGTM but @plemarquand should have a look

[plemarquand]

Looks good to me, thank you for this!

[award999]

@wcrd can you add a changelog entry please

[wcrd]

Rebased and added a changelog entry - it looks like the 2.6.1 title was duplicated so also removed that. LMK if OK! Thanks

[plemarquand]

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