Update specification/client_server_api.rst
Update specification/client_server_api.rst

Co-Authored-By: Kitsune Ral <25c4eaf873d39a7bf6a8849338b2091269d7dc97@users.sf.net>
matrix-org/matrix-doc,matrix-org/matrix-doc,matrix-org/matrix-doc,matrix-org/matrix-doc