Add some keyword of Swift 5.1

Author: taku0

swift-mode-font-lock.el

@@ -538,7 +538,7 @@ Return nil otherwise."
 (defconst swift-mode:declaration-keywords
   '("associatedtype" "class" "deinit" "enum" "extension" "fileprivate" "func"
     "import" "init" "inout" "internal" "let" "open" "operator" "private"
-    "protocol" "public" "static" "struct" "subscript" "typealias" "var")
+    "protocol" "public" "some" "static" "struct" "subscript" "typealias" "var")
   "Keywords used in declarations.")
 
 (defconst swift-mode:statement-keywords

swift-mode-lexer.el

@@ -416,9 +416,9 @@ Return nil otherwise." ;; FIXME pound-count
        ;; Suppress implicit semicolon around keywords that cannot start or end
        ;; statements.
        (member (swift-mode:token:text previous-token)
-               '("inout" "throws" "rethrows" "in" "where"))
+               '("some" "inout" "throws" "rethrows" "in" "where"))
        (member (swift-mode:token:text next-token)
-               '("inout" "throws" "rethrows" "in" "where")))
+               '("some" "inout" "throws" "rethrows" "in" "where")))
       nil)
 
      ;; Inserts semicolon before open curly bracket.

test/swift-files/indent/identifiers.swift

@@ -103,6 +103,9 @@ func foo() {
     foo(
       var: 1
     )
+    foo(
+      some: 1
+    )
 
     // Keywords used in statements
     foo(