Changes

spelling.txt: remove teh||the

TEH is a valid acronym in Osmocom+Themyscira universe: it stands
for TRAU-like Extension Header, as defined in this spec:

https://www.freecalypso.org/specs/tw-ts-001-v010100.txt

Various Osmocom components now include support for this family
of Themyscira specs, but the linter outright rejects any and all
patches that have a legitimate need to mention this acronym.

Change-Id: I3d429d723e6cf926ecca9a83e36445575786c228