TrimMultilineRawString support for alternate trimming methods

[samuelneff]

The TrimMultilineRawString (#5051) rule can be helpfully extended to allow custom trimming functions and chained functions.

Expected Behavior

Here is an example from our codebase:

fun String.collapseWhitespace(text: String) =
    trim().replace(Regex("\\s\\s+"), " ")

val blockWithoutAnyExtraWhitespace = """
    This is some text.

    Here is another line; spaced apart.
""".collapseWhitespace()

println(blockWithoutAnyExtraWhitespace)
// Prints: This is some text. Here is another line; spaced apart.

Current Behavior

Currently the rule requires trimIndent() or trimMargin() be called and nothing else is considered valid.

Context

See above example from our codebase that fails this rule but we would like to be able to pass.
Configuration with this change would include an additional option:

TrimMultilineRawString:
  additionalTrimmingMethods:
    - collapseWhitespace

Note: I'm working on another rule now for Hacktoberfest. If I actually get one done, I'll look into implementing this as well. Looks straightforward. Thanks for this great new rule!

[BraisGabin]

Good idea! But instead of additionalTrimmimgMethods I would call it trimmingMethods and add the two default ones.

Do you want me to assign this issue to you?

[samuelneff]

trimmingMethods

👍

assign this issue to you

hesitant 👍 😄

[BraisGabin]

Hahaha, no pressure ;)