doc: Re-order sections of "28.4. Progress Reporting"

doc: Re-order sections of "28.4. Progress Reporting"

BEFORE
28.4.1. ANALYZE Progress Reporting
28.4.2. CREATE INDEX Progress Reporting
28.4.3. VACUUM Progress Reporting
28.4.4. CLUSTER Progress Reporting
28.4.5. Base Backup Progress Reporting
28.4.6. COPY Progress Reporting

AFTER
28.4.1. ANALYZE Progress Reporting
28.4.2. CLUSTER Progress Reporting
28.4.3. COPY Progress Reporting
28.4.4. CREATE INDEX Progress Reporting
28.4.5. VACUUM Progress Reporting
28.4.6. Base Backup Progress Reporting

Author: Peter Smith <peter.b.smith@fujitsu.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/CAHut+Pv8Oa7v06hJb3+HzCtM2u-3oHWMdvXVHhvi7ofB83pNbg@mail.gmail.com