docs: update install guides to use FoBiS fetch instead of submodules

  Replace all references to recursive git clones and submodule
  initialization with plain `git clone` + `FoBiS.py fetch`. Also
  fix a copy-paste error in the README FoBiS dependency snippet
  (key was `PENF` pointing at the VecFor URL).

Author: szaghi

README.md

@@ -84,7 +84,7 @@ FoBiS.py install szaghi/VecFor -mode static-gnu --prefix /path/to/prefix
 ```ini
 [dependencies]
 deps_dir = src/third_party
-PENF     = https://github.com/szaghi/VecFor
+VecFor   = https://github.com/szaghi/VecFor
 ```
 
 ```bash

docs/guide/installation.md

@@ -18,17 +18,12 @@ VecFor is developed on GNU/Linux. Windows should work out of the box but is not
 
 ## Download
 
-VecFor uses **git submodules** for the [PENF](https://github.com/szaghi/PENF) dependency (portable numeric kind parameters). Clone recursively:
+Clone the repository and fetch the [PENF](https://github.com/szaghi/PENF) dependency automatically with FoBiS.py:
 
 ```bash
-git clone https://github.com/szaghi/VecFor --recursive
+git clone https://github.com/szaghi/VecFor
 cd VecFor
-```
-
-If you already have a non-recursive clone:
-
-```bash
-git submodule update --init --recursive
+FoBiS.py fetch   # downloads PENF into src/third_party/
 ```
 
 ### Minimal manual download
@@ -51,7 +46,7 @@ A minimal installation requires only `src/lib/vecfor.F90` (and PENF sources). Th
 │   │   ├── simple.f90      # Basic usage example
 │   │   └── kinds.f90       # Operator coverage test (all numeric kinds)
 │   └── third_party/
-│       └── PENF/           # Kind parameter definitions (git submodule)
+│       └── PENF/           # Kind parameter definitions (fetched by FoBiS.py)
 └── scripts/
     └── run_tests.sh        # Test runner
 ```

scripts/install.sh

@@ -46,9 +46,9 @@ function projectdownload () {
   fi
 
   if [ "$DOWNLOAD" == "git" ]; then
-    git clone --recursive $GITHUB
+    git clone $GITHUB
     cd $PROJECT
-    git submodule update --init --recursive
+    FoBiS.py fetch
     cd -
   elif [ "$DOWNLOAD" == "wget" ]; then
     wget $(curl -s https://api.github.com/repos/$USERNAME/$PROJECT/releases/latest | grep 'browser_' | cut -d\" -f4 | grep -i tar.gz)