[Omit needless words] Don't split setters, "action-like" methods.

Suggested by Brent Royal-Gordon.

lib/Basic/StringExtras.cpp

@@ -920,6 +920,7 @@ static bool splitBaseNameAfterLastPreposition(StringRef &baseName,
 /// Split the base name, if it makes sense.
 static bool splitBaseName(StringRef &baseName, StringRef &argName,
                           const OmissionTypeName &paramType,
+                          StringRef paramName,
                           StringScratchSpace &scratch) {
   // If there is already an argument label, do nothing.
   if (!argName.empty()) return false;
@@ -932,6 +933,16 @@ static bool splitBaseName(StringRef &baseName, StringRef &argName,
     return true;
   }
 
+  // Don't split anything that starts with "set".
+  if (camel_case::getFirstWord(baseName) == "set")
+    return false;
+
+  // Don't split a method that looks like an action (with a "sender"
+  // of type AnyObject).
+  if (paramName == "sender" &&
+      camel_case::getLastWord(paramType.Name) == "Object")
+    return false;
+
   // Try splitting after the last preposition.
   if (splitBaseNameAfterLastPreposition(baseName, argName, paramType, scratch))
     return true;
@@ -1013,7 +1024,8 @@ bool swift::omitNeedlessWords(StringRef &baseName,
 
   // If needed, split the base name.
   if (!argNames.empty() &&
-      splitBaseName(baseName, argNames[0], paramTypes[0], scratch))
+      splitBaseName(baseName, argNames[0], paramTypes[0], firstParamName,
+                    scratch))
     anyChanges = true;
 
   // Omit needless words based on parameter types.

test/IDE/Inputs/custom-modules/OmitNeedlessWords.h

@@ -4,4 +4,6 @@
 -(void)jumpToUrl:(nonnull NSURL *)url;
 -(BOOL)objectIsCompatibleWithObject:(nonnull id)other;
 -(void)insetByX:(NSInteger)x y:(NSInteger)y;
+-(void)setIndirectlyToValue:(nonnull id)object;
+-(void)jumpToTop:(nonnull id)sender;
 @end

test/IDE/print_omit_needless_words.swift

@@ -255,6 +255,8 @@
 // CHECK-OMIT-NEEDLESS-WORDS: func jumpTo(_: URL)
 // CHECK-OMIT-NEEDLESS-WORDS: func objectIsCompatibleWith(_: AnyObject) -> Bool
 // CHECK-OMIT-NEEDLESS-WORDS: func insetBy(x _: Int, y: Int)
+// CHECK-OMIT-NEEDLESS-WORDS: func setIndirectlyToValue(_: AnyObject)
+// CHECK-OMIT-NEEDLESS-WORDS: func jumpToTop(_: AnyObject)
 
 // Don't drop the 'error'.
 // CHECK-ERRORS: func tryAndReturnError(_: ()) throws