Update transport docs for location suffix (Revision D)

[FabianoEger]

Summary

• Adds the @= location suffix to the suffixes table in all four transport docs (HTTP, TCP, UDP, MQTT)
• Updates "all combined" examples to include the location suffix in the correct position (#UNIT @=LOCATION @TIMESTAMP ^GROUP {METADATA})
• Updates body-level defaults examples to include @=LOCATION as a body-level modifier (HTTP, MQTT)
• Updates location data examples to show value + location in a single variable (HTTP, UDP)
• Updates the introduction quick example to use body-level @= instead of a separate position variable

Aligns with tago-io/tagotip#1 (Revision D). The specification docs (tagotip-specification.md, tagotips-specification.md) are synced from the tagotip repo automatically and will update when that PR merges.

Test plan

• Verify all transport doc suffix tables show Location between Unit and Timestamp
• Verify "all combined" examples include @=lat,lng between #unit and @timestamp
• Verify body-level examples include @= before @TIMESTAMP
• Verify location push examples show the new suffix syntax
• Build docs site and check rendered pages