chore(proto-loader-gen-types): update option descriptions for consistency

Author: tenkirin

packages/proto-loader/README.md

@@ -104,10 +104,10 @@ Options:
       --outputBranded        Output property for branded type for  "restricted"
                              types with fullName of the Message as its value
                                                       [boolean] [default: false]
-      --targetFileExtension  File extension for generated files. Defaults to .ts
+      --targetFileExtension  File extension for generated files.
                                                        [string] [default: ".ts"]
       --importFileExtension  File extension for import specifiers in generated
-                             code. Defaults to none (omitted)           [string]
+                             code.                        [string] [default: ""]
 ```
 
 ### Example Usage

packages/proto-loader/bin/proto-loader-gen-types.ts

@@ -920,8 +920,8 @@ async function runScript() {
       outputTemplate: 'Template for mapping output or "restricted" type names',
       inputBranded: 'Output property for branded type for  "permissive" types with fullName of the Message as its value',
       outputBranded: 'Output property for branded type for  "restricted" types with fullName of the Message as its value',
-      targetFileExtension: 'File extension for generated files. Defaults to .ts',
-      importFileExtension: 'File extension for import specifiers in generated code. Defaults to none (omitted)'
+      targetFileExtension: 'File extension for generated files.',
+      importFileExtension: 'File extension for import specifiers in generated code.'
     }).demandOption(['outDir'])
     .demand(1)
     .usage('$0 [options] filenames...')