Support triple quoted strings in default value of config delegate

[marschwar]

This fixes the documentation generation for triple quoted default values in config delegates. This is particularly useful when it comes to regular expressions.

Previously the generated documentation for

@Configuration("description")
private val prop : String by config("""([.?!][ \t\n\r\f<])|([.?!:]$)""")

was incorrect. It was necessary to write

@Configuration("description")
private val prop : String by config("([.?!][ \\t\\n\\r\\f<])|([.?!:]\$)")

[codecov]

Codecov Report

Merging #3733 (13de1aa) into main (50b453b) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##               main    #3733   +/-   ##
=========================================
  Coverage     78.04%   78.04%           
  Complexity     2883     2883           
=========================================
  Files           473      473           
  Lines          9300     9300           
  Branches       1767     1767           
=========================================
  Hits           7258     7258           
  Misses         1078     1078           
  Partials        964      964           

Impacted Files	Coverage Δ	Complexity Δ
...urbosch/detekt/generator/collection/Annotations.kt	71.42% <100.00%> (ø)	0.00 <0.00> (ø)

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