makefile: minor cleanup (#3994)

- goimports is not used as a tool anymore
	- correct me if wrong
- rename devtools folder to merely tools.mk
- remove slate_header.txt

Signed-off-by: Marko Baricevic <marbar3778@yahoo.com>

Makefile

@@ -15,7 +15,7 @@ BUILD_FLAGS = -mod=readonly -ldflags "$(LD_FLAGS)"
 all: check build test install
 
 # The below include contains the tools.
-include scripts/devtools/Makefile
+include tools.mk
 include tests.mk
 
 ########################################
@@ -153,10 +153,6 @@ lint:
 
 DESTINATION = ./index.html.md
 
-rpc-docs:
-	cat rpc/core/slate_header.txt > $(DESTINATION)
-	godoc2md -template rpc/core/doc_template.txt github.com/tendermint/tendermint/rpc/core | grep -v -e "pipe.go" -e "routes.go" -e "dev.go" | sed 's,/src/target,https://github.com/tendermint/tendermint/tree/master/rpc/core,' >> $(DESTINATION)
-
 ###########################################################
 ### Docker image
 

rpc/core/README.md

@@ -1,15 +1,5 @@
 # Tendermint RPC
 
-We are using [Slate](https://github.com/lord/slate) to power our RPC
-documentation. For generating markdown use:
-
-```shell
-go get github.com/davecheney/godoc2md
-
-# from root of this repo
-make rpc-docs
-```
-
 ## Pagination
 
 Requests that return multiple items will be paginated to 30 items by default.

rpc/core/slate_header.txt

@@ -1,13 +0,0 @@
----
-title: RPC Reference
-
-language_tabs: # must be one of https://git.io/vQNgJ
-  - shell
-  - go
-
-toc_footers:
-  - <a href='https://tendermint.com/'>Tendermint</a>
-  - <a href='https://github.com/lord/slate'>Documentation Powered by Slate</a>
-
-search: true
----