pgsql: doc: Add unit to pg_shmem_allocations attributes

doc: Add unit to pg_shmem_allocations attributes

The unit of size and allocated_size was not documented. Speciyfing the
unit is in line with how many other (but not all) system view attributes
are documented so fixing by adding the unit which is "bytes".

Author: Euler Taveira <euler(at)eulerto(dot)com>
Reviewed-by: Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com>
Reported-by: coleman(dot)rik(at)gmail(dot)com
Discussion: https://postgr.es/m/166033703458.653.1583077816076994614@wrigleys.postgresql.org

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/75ca8c14576238926e1f4c2e80c11dd23a1911c3

Modified Files
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doc/src/sgml/system-views.sgml | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)