Add multilevel sections support and corresponding renaming

compiler/tests-spec/testData/diagnostics/notLinked/contracts/declarations/contractFunction/neg/1.kt

@@ -6,7 +6,7 @@
  KOTLIN DIAGNOSTICS NOT LINKED SPEC TEST (NEGATIVE)
 
  SECTION: contracts
- CATEGORY: declarations, contractFunction
+ CATEGORIES: declarations, contractFunction
  NUMBER: 1
  DESCRIPTION: Check that recursion isn't allowed in contract functions with CallsInPlace effect.
  */

compiler/tests-spec/testData/diagnostics/notLinked/contracts/declarations/contractFunction/neg/2.kt

@@ -7,7 +7,7 @@
  KOTLIN DIAGNOSTICS NOT LINKED SPEC TEST (NEGATIVE)
 
  SECTION: contracts
- CATEGORY: declarations, contractFunction
+ CATEGORIES: declarations, contractFunction
  NUMBER: 2
  DESCRIPTION: Check report about use contracts in literal functions, lambdas or not top-level functions.
  ISSUES: KT-26149

compiler/tests-spec/testData/diagnostics/notLinked/contracts/declarations/contractFunction/pos/1.kt

@@ -6,7 +6,7 @@
  KOTLIN DIAGNOSTICS NOT LINKED SPEC TEST (POSITIVE)
 
  SECTION: contracts
- CATEGORY: declarations, contractFunction
+ CATEGORIES: declarations, contractFunction
  NUMBER: 1
  DESCRIPTION: Check that fun with contract and CallsInPlace effect is an inline function.
  UNEXPECTED BEHAVIOUR

compiler/tests-spec/testData/diagnostics/notLinked/contracts/declarations/contractFunction/pos/2.kt

@@ -6,7 +6,7 @@
  KOTLIN DIAGNOSTICS NOT LINKED SPEC TEST (POSITIVE)
 
  SECTION: contracts
- CATEGORY: declarations, contractFunction
+ CATEGORIES: declarations, contractFunction
  NUMBER: 2
  DESCRIPTION: Contract function usage before declaration it
  */