Check presence of dispatch receiver parameter in modifier checks

Also fix typo in "inapplicable infix" diagnostic message

idea/testData/intentions/toInfixCall/packageFunctionCall.kt

@@ -1,9 +1,9 @@
 // IS_APPLICABLE: false
-// ERROR: 'infix' modifier is inapplicable on this function: must be a member of an extension function
+// ERROR: 'infix' modifier is inapplicable on this function: must be a member or an extension function
 package ppp
 
 infix fun foo(p: String){}
 
 fun main() {
     ppp.<caret>foo("")
-}
+}