Dealing with infix calls in completion

#KT-4846 Fixed

idea/testData/completion/handlers/InfixCall.kt

@@ -0,0 +1,5 @@
+fun <A, B> A.to(that: B): Pair<A, B> = Pair(this, that)
+
+fun foo() {
+    val pair = 1 to<caret>
+}

idea/testData/completion/handlers/InfixCall.kt.after

@@ -0,0 +1,5 @@
+fun <A, B> A.to(that: B): Pair<A, B> = Pair(this, that)
+
+fun foo() {
+    val pair = 1 to <caret>
+}

idea/testData/completion/handlers/InfixCallOnSpace.kt

@@ -0,0 +1,5 @@
+fun <A, B> A.to(that: B): Pair<A, B> = Pair(this, that)
+
+fun foo() {
+    val pair = 1 to<caret>
+}

idea/testData/completion/handlers/InfixCallOnSpace.kt.after

@@ -0,0 +1,5 @@
+fun <A, B> A.to(that: B): Pair<A, B> = Pair(this, that)
+
+fun foo() {
+    val pair = 1 to <caret>
+}

idea/testData/completion/handlers/multifile/InfixExtensionCallImport-1.kt

@@ -0,0 +1,3 @@
+fun foo() {
+    val pair = 1 makeP<caret>
+}

idea/testData/completion/handlers/multifile/InfixExtensionCallImport-2.kt

@@ -0,0 +1,3 @@
+package other
+
+fun <A, B> A.makePair(that: B): Pair<A, B> = Pair(this, that)

idea/testData/completion/handlers/multifile/InfixExtensionCallImport.kt.after

@@ -0,0 +1,5 @@
+import other.makePair
+
+fun foo() {
+    val pair = 1 makePair <caret>
+}