runtime: Change "process in the container" -> "container process"
runtime: Change "process in the container" -> "container process"

The latter is much more common:

  $ git --no-pager grep -ic "process in the container" origin/master -- *.md
  origin/master:runtime.md:1
  $ git --no-pager grep -ic "container process" origin/master -- *.md
  origin/master:config-linux.md:4
  origin/master:config.md:2
  origin/master:glossary.md:1
  origin/master:runtime.md:5

Signed-off-by: W. Trevor King <f75897670c17327c42ab201733fb8a81ff9f4c34@tremily.us>

wking/opencontainer-specs,laijs/specs,opencontainers/runtime-spec,hqhq/runtime-spec,wking/opencontainer-runtime-spec,opencontainers/specs,hqhq/specs