Improve ScalafmtDynamicError messages

[kitbellew]

Influenced by https://youtrack.jetbrains.com/issue/SCL-20123

[kitbellew]

@unkarjedy ptal, this sequence of changes should solve the problem and make one of the commits unnecessary: JetBrains/intellij-scala#614.

[unkarjedy]

Can we publish a version with this in order we can close https://youtrack.jetbrains.com/issue/SCL-20123?

[kitbellew]

@unkarjedy can't upgrade yet to the new version of scalameta parser, it interferes with the current implementation of RedundantParens rule. fix is out for review: #3207.

[unkarjedy]

@kitbellew
I might be out of context, but how upgrading to new scalameta parser can block publishing minor version with existing working code?

[kitbellew]

@unkarjedy perhaps because the parser change should have been released not as a patch but as a minor change.

the parser changed treatment of infix expressions with a side enclosed in parentheses; before, these parentheses were included as part of the side but not anymore.

this affected how the formatter has to deal with rewriting redundant parentheses...