Fix typo in progress reporting doc

Hi,

I have observed that the table naming conventions used in
'progress-reporting.html' are not consistent across different
sections. For some cases "Phases" (Table 28.37. CREATE INDEX Phases)
is used and for some cases "phases" (Table 28.35. ANALYZE phases) is
used. I have attached a patch to correct this.

Thanks and Regards,
Nitin Jahav