GRIB2_CodeFlag_4_2_CodeTable_en.csv: unit for code 19

[shahramn]

Branch

https://github.com/wmo-im/GRIB2/tree/issue74

Initial Statement

In this table, there is a Code Table entry 19 which reads:
19,,Precipitation type,,(4.201),Operational

This should be changed to:
19,,Precipitation type,,(Code table 4.201),Operational

Just like the other table entry 123 (Dominant precipitation type)

[amilan17]

Branch is updated and  it is already published correctly in the manual.