fix(common/web): replace invalid StrsItem identity checks with isEqual()

[markcsinclair]

In PR #12868 a new isEqual() mathod was added to StrsItem to distinguish identity (===) and equality (toEqual()) checks. This was needed to get correct behaviour from ElemElement.isEqual() and ElementString.isEqual() which both (now) depend on StrsItem.isEqual().

This PR checks uses of StrsItem to identify where StrsItem.toEqual() should be used instead of an identity check.

Files examined:

• element-string.ts
• kmx-plus.ts
• string-list.ts
• build-keys.ts
• build-layr.ts
• build-strs.ts
• build-uset.ts

Fixes: #12945

@keymanapp-test-bot skip

[keymanapp-test-bot]

User Test Results

Test specification and instructions

User tests are not required

Test Artifacts

• Android
  • Keyman for Android apk
  • FirstVoices for Android 16.0 apk
  • FirstVoices Keyboards for Android apk
  • KeyboardHarness apk
  • Keyman for Android 16.0 apk
  • KMSample1 apk
  • KMSample2 apk
• Developer
  • Keyman Developer
  • Compiler Regression Tests
  • kmcomp.zip
• iOS
  • Keyman for iOS (simulator image)
  • FirstVoices Keyboards for iOS (simulator image)
  • TestFlight internal PR build version - 18.0.183 (0.13122.12783)
• Keyboards
  • Test Keyboards
• Web
  • KeymanWeb Test Home
• Windows
  • Keyman for Windows
  • FirstVoices Keyboards for Windows
  • Text Editor (32 bit)
  • Text Editor (64 bit)

[markcsinclair]

In the end, no instances were found where identity was incorrectly used instead of the (new) StrsItem.toEqual(). In all cases, it seems that direct string comparison (StrsItem.value) was made rather than checks on the StrsItem. The only occasions where a bug was found were in the ElemElement.isEqual() and ElementString.isEqual(), corrected in earlier PR #12868.

This PR should still be merged, however, as it cointains some new unit tests.

[srl295]

I think it's worth doing the review, and the test, as isEqual would actually be the best way to compare.

It's entirely possible that a StrsItem will be used with isEqual in the future.

[keyman-server]

Changes in this pull request will be available for download in Keyman version 18.0.184-alpha