KT-20166: Replace type name when caret is at the end of param name

When caret is at the end ('f<caret>: Foo'), tokenAt was COLON,
not IDENTIFIER

#KT-20166 fixed

idea/idea-completion/testData/handlers/basic/parameterNameAndType/TabReplace3.kt

@@ -0,0 +1,6 @@
+class Foo
+
+fun f(f<caret>: Foo)
+
+// ELEMENT_TEXT: foo: Foo
+// CHAR: '\t'

idea/idea-completion/testData/handlers/basic/parameterNameAndType/TabReplace3.kt.after

@@ -0,0 +1,6 @@
+class Foo
+
+fun f(foo: Foo)
+
+// ELEMENT_TEXT: foo: Foo
+// CHAR: '\t'