[webview_flutter] Document NavigationDelegate callbacks

[saurabh-mirajkar]

Description

Adds documentation for callback parameters accepted by NavigationDelegate.

Previously, the constructor documentation only described onUrlChange, onHttpAuthRequest, and onSslAuthError, while other commonly used callbacks such as onNavigationRequest, onPageStarted, onPageFinished, onProgress, onWebResourceError, and onHttpError were undocumented.

This change updates the NavigationDelegate constructor documentation to cover all supported callbacks and improves consistency in the existing descriptions.

Fixes flutter/flutter#187780

Tests

Tests are not needed because this is a documentation-only change.

Version and CHANGELOG

No version or CHANGELOG updates are included because this change only adds documentation for existing callbacks and does not modify package behavior. If versioning updates are expected for public API documentation changes, I'm happy to add them.

Pre-Review Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I read the AI contribution guidelines and understand my responsibilities, or I am not using AI tools.
• I read the Tree Hygiene page, which explains my responsibilities.
• I read and followed the relevant style guides and ran the auto-formatter.
• I signed the CLA.
• The title of the PR starts with the name of the package surrounded by square brackets, e.g. [shared_preferences]
• I linked to at least one issue that this PR fixes in the description above.
• I followed the version and CHANGELOG instructions, using semantic versioning and the repository CHANGELOG style, or I have commented below to indicate which documented exception this PR falls under¹.
• I updated/added any relevant documentation (doc comments with ///).
• I added new tests to check the change I am making, or I have commented below to indicate which test exemption this PR falls under¹.
• All existing and new tests are passing.

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Footnotes

1. Regular contributors who have demonstrated familiarity with the repository guidelines only need to comment if the PR is not auto-exempted by repo tooling. ↩ ↩²

[gemini-code-assist]

Code Review

This pull request updates the documentation template for the NavigationDelegate constructor in packages/webview_flutter/webview_flutter/lib/src/navigation_delegate.dart to include descriptions for several callback parameters, including onNavigationRequest, onPageStarted, onPageFinished, onProgress, onWebResourceError, and onHttpError, while also making minor formatting adjustments to existing callback descriptions. There are no review comments, and I have no feedback to provide.

[stuartmorgan-g]

[x] I followed the version and CHANGELOG instructions, using semantic versioning and the repository CHANGELOG style, or I have commented below to indicate which documented exception this PR falls under1.

I'm not seeing this step in the PR.

[saurabh-mirajkar]

[x] I followed the version and CHANGELOG instructions, using semantic versioning and the repository CHANGELOG style, or I have commented below to indicate which documented exception this PR falls under1.

I'm not seeing this step in the PR.

@stuartmorgan-g Thanks for pointing that out. I've updated the PR description to explain why I didn't include version or CHANGELOG updates, since this change only adds documentation for existing callbacks and does not modify package behavior. If public API documentation changes are expected to include versioning or CHANGELOG updates under the packages repository policy, I'm happy to add them.