Allow for escaped newlines in modules and headings

[CMDJojo]

Describe the bug
The language supports escaping new lines with \ directly preceeding the newline in paragraph text, and the intuition is (or should be) that it always does. However, it doesn't in module bodies, module invocations and headings due to searching for whitespace/newlines.

To Reproduce
This works:

# Heading at level 1
[foo arg1 arg2]"body text"

This, however, should produce the same result if backslashes always escapes newlines:

# Heading at \
level 1
[foo arg1 \
arg2]"body \
text"

Expected behavior
The two code blocks above should be parsed to the same AST

Additional context
There is probably a use for a custom parser taking a parser and applying it on the same line, taking escaped newlines into account. Using it in both heading parsing, module invocation parsing, module body parsing and paragraph text parsing should sync the behaviour up between the three contextes.