This patch is derived from [1]. While reviewing that thread, I noticed that when the documentation refers to .h and .cfiles in the PostgreSQL source tree, it uses a mix of full source-tree paths and short relative paths. This inconsistency can be confusing for future documentation authors, who may be unsure which form to use.
This patch aims to make the usage consistent. When the documentation explicitly refers to a file’s location in the source tree (for example, “in the file …”, "see the file ..."), it uses the full path. When the documentation refers to a header in the context of inclusion, it uses the short relative path, matching the form used in #include <header> directives.
