docs: fix errata in provideEnvironmentInitializer API docs

[davidlj95]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/angular/angular/blob/main/CONTRIBUTING.md#commit
• N/A Tests for the changes have been added (for bug fixes / features)
• N/A Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Documentation content changes
• angular.dev application / infrastructure changes
• Other... Please describe:

What is the current behavior?

Wrong function name in recently introduced provideEnvironmentInitializer function

Issue Number: N/A

What is the new behavior?

Use the proper function name

Does this PR introduce a breaking change?

• Yes
• No

Other information

[AndrewKushnir]

@davidlj95 thanks for improving Angular docs!

[AndrewKushnir]

Caretaker note: no presubmit required, docs-only change.

[alxhub]

This PR was merged into the repository by commit 317d704.

The changes were merged into the following branches: main, 19.0.x

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