Replace spaces with 2 tabs

Author: shogohida

src/cmd/go/internal/generate/generate.go

@@ -91,10 +91,10 @@ Go generate sets several variables when it runs the generator:
 	$DOLLAR
 		A dollar sign.
 	$PATH
-    	The $PATH of the parent process, with $GOROOT/bin
-    	placed at the beginning. This causes generators
-    	that execute 'go' commands to use the same 'go'
-    	as the parent 'go generate' command.
+		The $PATH of the parent process, with $GOROOT/bin
+		placed at the beginning. This causes generators
+		that execute 'go' commands to use the same 'go'
+		as the parent 'go generate' command.
 
 Other than variable substitution and quoted-string evaluation, no
 special processing such as "globbing" is performed on the command