Misleading message for --dry-run with --replace

[norrisgc]

If you specify both --dry-run (or -n) and --replace (or -replace, -r or -i) you get a message stating "cannot use --dry-run and --in-place at the same time".

The problem is that there is no --in-place option. inPlace is however the internal variable name used for --replace. There's two possible fixes:

1. Change the message. This could affect anything which tries to use the message in some kind of script.
2. Add the --in-place option at line 68 in CommandLineOptionsParser.java and related help text. This should not affect anything else.

[rootkiller6788]

Hit this exact message today and it threw me for a second, since --in-place is not a flag the tool accepts. The option is -i/-r/-replace/--replace, so the usage error names something that does not exist.

I went with option 1 from the description: changed the message to point at --replace (the long form shown in --help). I also updated the CLI test so it triggers the error through both --replace --dry-run and the -i -n shorthand, instead of only the shorthand.

Tested with mvn -pl core test -Dtest=CommandLineFlagsTest; all 8 pass. Will open a PR.