Add a new make -C doc alldeps target to install Documenter (#58504)

This adds a new `alldeps` target to `make -C doc` that also downloads
the Documenter.jl dependency. The motivation here is to make sure to
have all dependencies necessary for running the doctests in an
environment that may not have network connectivity (e.g. the OpenAI
Codex sandbox).

Author: Keno

doc/Makefile

@@ -34,6 +34,9 @@ deps: $(SRCCACHE)/UnicodeData-$(UNICODE_DATA_VERSION).txt
 	$(JLCHECKSUM) "$<"
 	cp "$<" UnicodeData.txt
 
+alldeps: deps
+	$(JULIA_EXECUTABLE) --color=yes $(call cygpath_w,$(SRCDIR)/make.jl) deps
+
 checksum-unicodedata: $(SRCCACHE)/UnicodeData-$(UNICODE_DATA_VERSION).txt
 	$(JLCHECKSUM) "$<"
 

doc/make.jl

@@ -8,6 +8,10 @@ push!(DEPOT_PATH, abspath(Sys.BINDIR, "..", "share", "julia"))
 using Pkg
 Pkg.instantiate()
 
+if "deps" in ARGS
+    exit()
+end
+
 using Documenter
 import LibGit2