Add an example showing footnote definitions and their associated trailing whitespace.

org_mode_samples/footnote_definition/Makefile

@@ -0,0 +1,23 @@
+SHELL := bash
+.ONESHELL:
+.SHELLFLAGS := -eu -o pipefail -c
+.DELETE_ON_ERROR:
+MAKEFLAGS += --warn-undefined-variables
+MAKEFLAGS += --no-builtin-rules
+SRCFILES := $(wildcard *.org)
+OUTFILES := $(patsubst %.org,%.tree.txt,$(SRCFILES))
+
+ifeq ($(origin .RECIPEPREFIX), undefined)
+  $(error This Make does not support .RECIPEPREFIX. Please use GNU Make 4.0 or later)
+endif
+.RECIPEPREFIX = >
+
+.PHONY: all
+all: $(OUTFILES)
+
+.PHONY: clean
+clean:
+> rm -rf $(OUTFILES)
+
+%.tree.txt: %.org ../common.el ../dump_org_ast.bash
+> ../dump_org_ast.bash $< $@

org_mode_samples/footnote_definition/simple.org

@@ -0,0 +1,8 @@
+[fn:1] A footnote.
+
+[fn:2] A multi-
+
+line footnote.
+
+
+not in the footnote.