refactor(packaging): simplify building docs

Fixes #101

Why?

- no build.rs that is invoked on _any_ `cargo build/run`
- no extra dev dependency
- no intermediate `docs/*.out` files
- 3 lines of bash instead
- maximum gzip compression (-9/--best)
- docs will be built only when needed,
    i.e. on `make docs` or `make install`

To quickly check:

```sh
make TARGET_DIR=/tmp/wayshot MAN{1,7}_DIR=/tmp/wayshot install
```

.gitignore

@@ -1,4 +1,3 @@
 target
 *.gz
-*.out
 .direnv

Makefile

@@ -13,7 +13,13 @@ build:
 run:
 	@cargo run
 
+docs:
 install: build
+	@for scd in ./docs/*.scd; do \
+		scdoc < "$$scd" | gzip --best > "$${scd%.scd}.gz" & \
+	done
+
+install: build docs
 	@mkdir -p $(TARGET_DIR)
 	@cp $(SOURCE_DIR)/$(BINARY) $(TARGET_DIR)
 	@chmod +x $(TARGET_DIR)/$(BINARY)
@@ -37,4 +43,4 @@ setup:
 	@rustup install stable
 	@rustup default stable
 
-.PHONY: check clean setup all install build
+.PHONY: check clean setup all install build docs

wayshot/Cargo.toml

@@ -10,9 +10,6 @@ keywords.workspace = true
 license.workspace = true
 repository.workspace = true
 
-[build-dependencies]
-flate2 = "1.0.27"
-
 [dependencies]
 tracing.workspace = true