smalltown -> metropolis

This pass removes all mentions of Smalltown, both from code and comments,
and replaces them with appropriate new terminology.

Test Plan: Refactor, covered by CI.

X-Origin-Diff: phab/D674
GitOrigin-RevId: 04a94d44ef07d46f7821530da5614daefe16d7ea
diff --git a/build/savestdout/README.md b/build/savestdout/README.md
index a233620..c6faada 100644
--- a/build/savestdout/README.md
+++ b/build/savestdout/README.md
@@ -5,7 +5,7 @@
 a shell.
 
 It was made to be used in Bazel rule definitions that want to run a command and save
-its output to stdout without going through ctx.actions.run_shell.
+its output to stdout without going through `ctx.actions.run\_shell`.
 
 Once [bazelbuild/bazel/issues/5511](https://github.com/bazelbuild/bazel/issues/5511)
 gets fixed, rules that need this behaviour can start using native Bazel functionality
@@ -19,4 +19,4 @@
     bazel build //build/savestdout
     bazel run bazel-bin/build/savestdout/*/savestdout /tmp/foo ps aux
 
-For an example of use in rules, see `smalltown_initramfs` in `//code/def.bzl`.
+For an example of use in rules, see `node_initramfs` in `//code/def.bzl`.