Don't right-align escaped newlines (e.g. for #define)

[Ivorforce]

Removes whitespace indentation for escaped newlines.

Motivation

This decouples the lines from one another for git diff purposes: When the backslashes are right-aligned, a change to the max size of the block changes all lines in it.
This leads to unnecessarily long change lists, increasing the chance and difficulty of merge conflicts, and makes it harder to view changes to these blocks in GitHub (e.g. https://github.com/godotengine/godot/pull/78971/files, though notably, the "hide whitespace" option helps, if you know it exists). In addition, the git blame is unnecessarily modified, and line history browsers are harder to use.

It also makes it hard to hand-align these blocks, which means you need to run pre-commit while working on the code, or risk pre-commit changing it later. For me, this has led to unnecessary local recompilations.

Downsides

The main downside to this is that the code is arguably harder to read.
Given that C macros lead to difficult to read and error-prone code (for example, they are not hygienic), we should be limiting their use anyway (and we do, for the most part). So I think this is an acceptable caveat.

[bruvzg]

The main downside to this is that the code is arguably harder to read.

Since it's space aligned and the rest of code use tab indentation, it's already a mess unless you are using the same tab size. So it's actually might improve readability in some cases.

[AThousandShips]

If it were possible to force it to add a few more spaces after each line I think that would help any readability concerns from this but I don't think clang supports that

[Repiteo]

Approved in buildsystem meeting! Will be good to merge after a rebase

[Repiteo]

Thanks!