Remove force unwrapping for source location

Companion of swiftlang/swift-syntax#1532

Author: kimdv

Sources/SwiftFormatCore/Finding+Convenience.swift

@@ -14,18 +14,7 @@ import SwiftSyntax
 
 extension Finding.Location {
   /// Creates a new `Finding.Location` by converting the given `SourceLocation` from `SwiftSyntax`.
-  ///
-  /// If the source location is invalid (i.e., any of its fields are nil), then the initializer will
-  /// return nil.
-  public init?(_ sourceLocation: SourceLocation) {
-    guard
-      let file = sourceLocation.file,
-      let line = sourceLocation.line,
-      let column = sourceLocation.column
-    else {
-      return nil
-    }
-
-    self.init(file: file, line: line, column: column)
+  public init(_ sourceLocation: SourceLocation) {
+    self.init(file: sourceLocation.file, line: sourceLocation.line, column: sourceLocation.column)
   }
 }

Sources/swift-format/Utilities/Diagnostic.swift

@@ -36,9 +36,9 @@ struct Diagnostic {
 
     /// Creates a new diagnostic location from the given source location.
     init(_ sourceLocation: SourceLocation) {
-      self.file = sourceLocation.file!
-      self.line = sourceLocation.line!
-      self.column = sourceLocation.column!
+      self.file = sourceLocation.file
+      self.line = sourceLocation.line
+      self.column = sourceLocation.column
     }
 
     /// Creates a new diagnostic location with the given finding location.