analyze_bcpf: Indent multi-line text to improve formatting

Addresses a comment on the review of the initial changes to add
analyze_bcpf script.

Bug: 202154151
Test: m analyze_bcpf && analyze_bcpf --bcpf art-bootclasspath-fragment
      m analyze_bcpf && analyze_bcpf --bcpf art-bootclasspath-fragment --fix
      atest --host analyze_bcpf_test
Change-Id: I8c030dcc1a29f106ca57dca8c97a5cb4425e7674