Backport Protobuf changes (#75)

* Backport Protobuf changes

* Changing comment to use has_committed_mutations

Author: schmidt-sebastian

firebase-firestore/src/proto/google/firebase/firestore/proto/maybe_document.proto

@@ -34,7 +34,8 @@ message NoDocument {
   google.protobuf.Timestamp read_time = 2;
 }
 
-// A message indicating that the document that is known to exist but its data is unknown.
+// A message indicating that the document that is known to exist but its data
+// is unknown.
 message UnknownDocument {
   // The name of the document that is known to exist, in the standard format:
   // `projects/{project_id}/databases/{database_id}/documents/{document_path}`
@@ -44,8 +45,9 @@ message UnknownDocument {
   google.protobuf.Timestamp version = 2;
 }
 
-// Represents either an existing document, the explicitly known absence of a document, or a document
-// that is known to exist (at some version) but whose contents are unknown
+// Represents either an existing document, the explicitly known absence of a
+// document, or a document that is known to exist (at some version) but whose
+// contents are unknown.
 message MaybeDocument {
   oneof document_type {
     // Used if the document is known to not exist.
@@ -54,12 +56,13 @@ message MaybeDocument {
     // The document (if it exists).
     google.firestore.v1beta1.Document document = 2;
 
-    // Used if the document is known to exist but its data is unknown
+    // Used if the document is known to exist but its data is unknown.
     UnknownDocument unknown_document = 3;
   }
 
-  // `hasCommittedMutations` marks documents that were written to the remote socument store based
-  // on a write acknowledgment. These documents are potentially inconsistent with the  backend's
-  // copy and use the write's commit version as their document version.
-  bool hasCommittedMutations = 4;
+  // `has_committed_mutations` marks documents that were written to the remote
+  // document store based on a write acknowledgment. These documents are
+  // potentially inconsistent with the backend's copy and use the write's
+  // commit version as their document version.
+  bool has_committed_mutations = 4;
 }