Add fail mode to exit with non-zero status if no matches found

[catatsuy]

This pull request introduces a new failMode feature to the CLI tool, which ensures the program exits with a specific status code if no matches are found during a replace operation. It also adjusts the exit codes for various error scenarios.

Key changes include:

New Feature: failMode

• Added failMode boolean flag to the CLI struct and its associated command-line flag. (internal/cli/cli.go) [1] [2]
• Updated the replaceProcess method to return a boolean indicating whether any matches were found. (internal/cli/cli.go) [1] [2]
• Modified the Run method to check the failMode flag and exit with a new ExitCodeNoMatch if no matches are found. (internal/cli/cli.go) [1] [2]

Exit Code Adjustments

• Changed the exit codes for ExitCodeParseFlagError and ExitCodeFail to 2, and introduced ExitCodeNoMatch with a value of 1. (internal/cli/cli.go)

Test Updates

• Updated existing tests and added new tests to cover the failMode feature and adjusted exit codes. (internal/cli/cli_test.go) [1] [2] [3] [4] [5] [6] [7] [8]
• Modified the ReplaceProcess method in the test export file to match the new signature. (internal/cli/export_test.go)