note about analyzer warnings in generated files (simolus3#223)

Add note about suppressing analyzer warnings for generated files.

Closes simolus3#222

(cherry picked from commit 4b809ec)

README.md

@@ -137,6 +137,21 @@ pub run build_runner build
 
 You'll now find a `.g.dart` file containing code to interact with the contract.
 
+#### Optional: Ignore naming suggestions for generated files
+
+If importing contract ABIs with function names that don't follow dart's naming conventions, the dart analyzer will (by default) be unhappy about it, and show warnings.
+This can be mitigated by excluding all the generated files from being analyzed.  
+Note that this has the side effect of suppressing serious errors as well, should there exist any. (There shouldn't as these files are automatically generated).
+
+Create a file named `analysis_options.yaml` in the root directory of your project:
+```
+analyzer:
+  exclude: 
+    - '**/*.g.dart'
+```
+
+See [Customizing static analysis](https://dart.dev/guides/language/analysis-options) for advanced options.
+
 ## Feature requests and bugs
 
 Please file feature requests and bugs at the [issue tracker][tracker].