Document support for platforms

The platform support is now near to complete, so worth mentioning.

Author: per1234

README.md

@@ -8,6 +8,7 @@
 
 - Sketches
 - Libraries
+- Boards platforms
 
 ## Documentation
 

internal/cli/cli.go

@@ -34,7 +34,7 @@ func Root() *cobra.Command {
 	rootCommand.PersistentFlags().String("compliance", "specification", "Configure how strict the tool is. Can be {strict|specification|permissive}")
 	rootCommand.PersistentFlags().String("format", "text", "The output format can be {text|json}.")
 	rootCommand.PersistentFlags().String("library-manager", "", "Configure the rules for libraries in the Arduino Library Manager index. Can be {submit|update|false}.\nsubmit: Also run additional rules required to pass before a library is accepted for inclusion in the index.\nupdate: Also run additional rules required to pass before new releases of a library already in the index are accepted.\nfalse: Don't run any Library Manager-specific rules.")
-	rootCommand.PersistentFlags().String("project-type", "all", "Only check projects of the specified type and their subprojects. Can be {sketch|library|all}.")
+	rootCommand.PersistentFlags().String("project-type", "all", "Only check projects of the specified type and their subprojects. Can be {sketch|library|platform|all}.")
 	rootCommand.PersistentFlags().Bool("recursive", false, "Search path recursively for Arduino projects to check. Can be {true|false}.")
 	rootCommand.PersistentFlags().String("report-file", "", "Save a report on the rules to this file.")
 	rootCommand.PersistentFlags().BoolP("verbose", "v", false, "Show more information while running rules.")

internal/rule/rulefunction/platform.go

@@ -1218,7 +1218,7 @@ func PlatformTxtRecipeSOPatternExtraFlagsSupport() (result ruleresult.Type, outp
 	return ruleresult.Pass, ""
 }
 
-// PlatformTxtRecipeArPatternMissing checks for missing recipe.ar.o.pattern property in platform.txt.
+// PlatformTxtRecipeArPatternMissing checks for missing recipe.ar.pattern property in platform.txt.
 func PlatformTxtRecipeArPatternMissing() (result ruleresult.Type, output string) {
 	if !projectdata.PlatformTxtExists() {
 		return ruleresult.Skip, "Platform has no platform.txt"
@@ -1256,7 +1256,7 @@ func PlatformTxtRecipeArPatternLTMinLength() (result ruleresult.Type, output str
 	return ruleresult.Pass, ""
 }
 
-// PlatformTxtRecipeArPatternExtraFlagsSupport checks if platform.txt recipe.ar.o.pattern provides support for user extra flags.
+// PlatformTxtRecipeArPatternExtraFlagsSupport checks if platform.txt recipe.ar.pattern provides support for user extra flags.
 func PlatformTxtRecipeArPatternExtraFlagsSupport() (result ruleresult.Type, output string) {
 	if !projectdata.PlatformTxtExists() {
 		return ruleresult.Skip, "Platform has no platform.txt"