fix: clarify README for this change

README.md

@@ -82,12 +82,28 @@ apigeelint -x ./externalPlugins -s path/to/your/apiproxy -f table.js
 ```
 Where `-x` points to the directory containing externally developed plugins.
 
-You could, for example, specify your own plugin for naming conventions, and exclude the builtin plugin with this:
+You could, for example, create your own plugin for naming conventions, and
+exclude the builtin plugin that enforces naming conventions (`PO007`) with the
+`-e` option:
+
 ```
 apigeelint -x ./externalPlugins -e PO007 -s path/to/your/apiproxy -f table.js
 ```
 
-This would effectively override the naming conventions that apigeelint checks.
+This would effectively override the built-in naming conventions that apigeelint checks.
+
+
+#### Excluding plugins
+
+You can, of course, exclude plugins without providing a replacement implementation:
+
+```
+apigeelint -s path/to/your/apiproxy -f table.js -e PO007,ST003
+```
+
+The above would exclude the policy naming convention check (`PO007`), and would
+also not check for conditions on an ExtractVariables with a JSONPayload
+(`ST003`), if for some reason you wanted to do that.
 
 
 #### Writing output to a file
@@ -97,11 +113,12 @@ apigeelint -s sampleProxy/apiproxy -f table.js -w existing-outputdir --quiet
 
 The `-w` option can point to an existing directory, in which case the output
 will be emitted to a file named apigeelint.out in that directory, in whatever
-format you specify. An existing file by that name will be overwritten. If the
+format you specify with `-f`. An existing file by that name will be overwritten. If the
 `-w` option is not a directory, it is treated as the name of a file, and output
 is written there.
 
-If you do not also specify `--quiet` the report will go to both stdout and to the specified filesystem destination.
+If you do not also specify `--quiet` the report will go to both stdout and to
+the specified filesystem destination.