aconfig: rename enum Format -> enum DumpFormat

Rename enum Format to enum DumpFormat to make it more apparent what it
refers to.

Bug: 279485059
Test: atest aconfig.test
Change-Id: I869be020b69618b036fa05247f155d9e35ff85e2
diff --git a/tools/aconfig/src/main.rs b/tools/aconfig/src/main.rs
index 513e313..b9ce259 100644
--- a/tools/aconfig/src/main.rs
+++ b/tools/aconfig/src/main.rs
@@ -53,7 +53,7 @@
                 .arg(
                     Arg::new("format")
                         .long("format")
-                        .value_parser(EnumValueParser::<commands::Format>::new())
+                        .value_parser(EnumValueParser::<commands::DumpFormat>::new())
                         .default_value("text"),
                 )
                 .arg(Arg::new("out").long("out").default_value("-")),