document .profile and .sh/profile

.profile

@@ -6,5 +6,17 @@ if [ -n "$BASH_VERSION" ]; then
 	[ -f "$HOME/.bashrc" ] && \
 	. "$HOME/.bashrc"
 else
+	# If I were to unconditionally source `.sh/profile`,
+	# I would have to un-source it from `.bash_profile`,
+	# and rename all Bash startup-files
+	# to force Bash to source `.profile` instead.
+	# The problem is, users (including myself)
+	# would have to rm all Bash startup-files too.
 	. "$HOME/.sh/profile"
+	# A possible solution to the previous problem,
+	# is to inline `.sh/profile` into `.profile` and
+	# make `.bash_profile` source that instead.
+	# This doesn't seem to have any cons, only pros,
+	# such as making `.profile` fully POSIX-compliant
+	# and (mostly) shell-agnostic
 fi