Add Tcl linting documentation to README

Co-authored-by: nikosavola <7860886+nikosavola@users.noreply.github.com>

README.md

@@ -2,3 +2,32 @@
 A schematic editor for VLSI/Asic/Analog custom designs, netlist backends for VHDL, Spice and Verilog. The tool is focused on hierarchy and parametric designs, to maximize circuit reuse.
 
 [Manual and instructions](http://repo.hu/projects/xschem/xschem_man/xschem_man.html)
+
+## Development
+
+### Tcl Code Linting and Formatting
+
+This project uses [tclint](https://github.com/nmoroze/tclint) for linting and formatting Tcl files.
+
+To install tclint:
+```bash
+pip install tclint
+```
+
+To check Tcl code formatting:
+```bash
+tclfmt --check --exclude "src/xschem.tcl" .
+```
+
+To automatically format Tcl files:
+```bash
+tclfmt --in-place --exclude "src/xschem.tcl" .
+```
+
+To run the linter:
+```bash
+find . -name "*.tcl" -type f ! -path "./src/xschem.tcl" -exec tclint -c .tclint.toml {} \;
+```
+
+The configuration for tclint can be found in `.tclint.toml`.
+