Name Suggester: Allow any Kotlin identifier in suggested names

#KT-10332 Fixed

idea/testData/refactoring/introduceVariable/NoExplicitReceiversUnresolved.kt.after

@@ -1,5 +1,5 @@
 fun main(args: Array<String>) {
-    val a = a1
-    println(a)
+    val a1 = a1
+    println(a1)
     println(a2)
 }

idea/testData/refactoring/nameSuggester/ExtensionFunction1.kt

@@ -0,0 +1,10 @@
+fun foo(): Int.(Int) -> Int = { 1 }
+
+fun test() {
+    <selection>foo()</selection>
+}
+
+/*
+foo
+function
+*/

idea/testData/refactoring/nameSuggester/ExtensionFunction2.kt

@@ -0,0 +1,10 @@
+fun foo(): Int.(Int, Int) -> Int = { 1 }
+
+fun test() {
+    <selection>foo()</selection>
+}
+
+/*
+foo
+function
+*/

idea/testData/refactoring/nameSuggester/Function1.kt

@@ -0,0 +1,10 @@
+fun foo(): (Int) -> Int = { 1 }
+
+fun test() {
+    <selection>foo()</selection>
+}
+
+/*
+foo
+function
+*/

idea/testData/refactoring/nameSuggester/Function2.kt

@@ -0,0 +1,10 @@
+fun foo(): (Int, Int) -> Int = { 1 }
+
+fun test() {
+    <selection>foo()</selection>
+}
+
+/*
+foo
+function
+*/

idea/testData/refactoring/nameSuggester/IdWithDigits.kt

@@ -0,0 +1,9 @@
+class Test123
+
+fun foo() {
+    <selection>Test123()</selection>
+}
+
+/*
+test123
+*/

idea/testData/refactoring/nameSuggester/IdWithNonASCII.kt

@@ -0,0 +1,9 @@
+class Тест123
+
+fun тест() {
+    <selection>Тест123()</selection>
+}
+
+/*
+тест123
+*/