Removes redundant spaces in single tokens with multiline separators

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Now cases when a single keyword is split by multiple multiline separators are supported.

work\
 spa\
 ce {
}

Also fixes redundant spaces inside quoted strings. The following code was parsed as "Soft ware System" before.

"Soft\
   ware \
   Sys\
   tem"

BREAKING CHANGE! The following code produced valid workspace before, because whitespaces in the second line were preserved. Now the first three lines will produce a single token workspace{.

workspace\
 \
  {
}

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@simonbrowndotje , could you please take a look?

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@simonbrowndotje, hello, it's unfortunate that the change is rejected. Is there anything I can do to apply the change to the language?