[FIR] Improve diagnostic reporting & don't use error symbol for candidate if possible

Also introduce few new diagnostics:
- NONE_APPLICABLE more many inapplicable candidates
- HIDDEN for visible candidates

compiler/testData/diagnostics/tests/smartCasts/objectLiterals/exclexcl.fir.kt

@@ -16,7 +16,7 @@ fun foo(): Int {
         k.run()
         val d: Int = c
         // a is not null because of k constructor, but we do not know it
-        return a <!INAPPLICABLE_CANDIDATE!>+<!> d
+        return a <!NONE_APPLICABLE!>+<!> d
     }
     else return -1
 }

compiler/testData/diagnostics/tests/smartCasts/objectLiterals/exclexclArgument.fir.kt

@@ -11,7 +11,7 @@ fun foo(): Int {
         }
         k.run()
         val d: Int = c
-        return a <!INAPPLICABLE_CANDIDATE!>+<!> d
+        return a <!NONE_APPLICABLE!>+<!> d
     }
     else return -1
 }

compiler/testData/diagnostics/tests/smartCasts/objectLiterals/exclexclTwoArgument.fir.kt

@@ -15,7 +15,7 @@ fun foo(): Int {
         }
         k.run()
         val d: Int = c
-        return a <!INAPPLICABLE_CANDIDATE!>+<!> d
+        return a <!NONE_APPLICABLE!>+<!> d
     }
     else return -1
 }