[ConstraintSystem] Reformat type inference debug output to use |

[amritpan]

This replaces the () grouping in the type inference debug output to use | instead to make it easier to follow nested solver steps.

  | Potential Binding(s): 
  `- $T1 [attributes: delayed, [literal: integer]] [with possible bindings: (default type of literal) Int]
  `- $T2 [attributes: delayed, [literal: string]] [with possible bindings: (default type of literal) String]
  `- Disjunction(s) = [$T0]
  {
    !> Attempting disjunction choice $T0 bound to decl Swift.(file).String extension.+ : (String.Type) -> (String, String) -> String [[locator@0x13e9bae00 [OverloadedDeclRef@/Users/amritpankaur/test.swift:81:3]]];
    |  Overload set choice binding $T0 := (String, String) -> String
    |
    `-> Considering -> (_const $T1, _const $T2) -> $T3 applicable fn $T0 [[locator@0x13e9bc5f0 [Binary@/Users/amritpankaur/test.swift:81:3 -> apply function]]];
    |  `- Simplification result:
    |    `- Added constraint: $T1 operator arg conv String [[locator@0x13e9bc6c0 [Binary@/Users/amritpankaur/test.swift:81:3 -> apply argument -> comparing call argument #0 to parameter #0]]];)
    |    `- Added constraint: $T2 operator arg conv String [[locator@0x13e9bc760 [Binary@/Users/amritpankaur/test.swift:81:3 -> apply argument -> comparing call argument #1 to parameter #1]]];)
    |    `- Removed constraint: (_const $T1, _const $T2) -> $T3 applicable fn $T0 [[locator@0x13e9bc5f0 [Binary@/Users/amritpankaur/test.swift:81:3 -> apply function]]];
    |  `-- Outcome: simplified
    |
    |  * Changes:
    |  | Newly Bound: 
    |  |  > $T0 := (String, String) -> String
    |  |  > $T3 := String
    |  | Added Constraints: 
    |  |  > $T1 operator arg conv String [[locator@0x13e9bc6c0 [Binary@/Users/amritpankaur/test.swift:81:3 -> apply argument -> comparing call argument #0 to parameter #0]]];
    |  |  > $T2 operator arg conv String [[locator@0x13e9bc760 [Binary@/Users/amritpankaur/test.swift:81:3 -> apply argument -> comparing call argument #1 to parameter #1]]];
    |  | Removed Constraint: 
    |  |  > (_const $T1, _const $T2) -> $T3 applicable fn $T0 [[locator@0x13e9bc5f0 [Binary@/Users/amritpankaur/test.swift:81:3 -> apply function]]];
    |
    ...
  }