perf(cli): optimize CPU consumption of help pages (#9607)

This change reduces the CPU consumption of --help by ~50%.

Also, this change removes ANSI escape codes from our golden files. I
don't think those were worth the inability to parallelize golden file tests and
global state fragility.

cli/testdata/coder_dotfiles_--help.golden

@@ -1,6 +1,6 @@
 coder v0.0.0-devel
 
-USAGE:
+USAGE:
   coder dotfiles [flags] <git_repo_url>
 
   Personalize your workspace by applying a canonical dotfiles repository
@@ -9,17 +9,17 @@ coder v0.0.0-devel
   
        $ coder dotfiles --yes git@github.com:example/dotfiles.git
 
-OPTIONS:
-  -b, --branch string
+OPTIONS:
+  -b, --branch string
           Specifies which branch to clone. If empty, will default to cloning the
           default branch or using the existing branch in the cloned repo on
           disk.
 
-      --symlink-dir string, $CODER_SYMLINK_DIR
+      --symlink-dir string, $CODER_SYMLINK_DIR
           Specifies the directory for the dotfiles symlink destinations. If
           empty, will use $HOME.
 
-  -y, --yes bool
+  -y, --yes bool
           Bypass prompts.
 
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