Add tcl extension (zed-industries#2693)

This extension adds some highlight bindings from the Tree-Sitter TCL
grammar to highlight TCL files. Let me know if I named something poorly.

Thanks!

Author: richnou

.gitmodules

@@ -2022,6 +2022,10 @@
 	path = extensions/tanuki
 	url = https://github.com/dylf/zed-tanuki.git
 
+[submodule "extensions/tcl"]
+	path = extensions/tcl
+	url = https://github.com/richnou/kissb-zed-tcl.git
+
 [submodule "extensions/templ"]
 	path = extensions/templ
 	url = https://github.com/makifdb/zed-templ.git

extensions.toml

@@ -2068,6 +2068,10 @@ version = "0.6.0"
 submodule = "extensions/tanuki"
 version = "0.0.1"
 
+[tcl]
+submodule = "extensions/tcl"
+version = "0.0.1"
+
 [templ]
 submodule = "extensions/templ"
 version = "0.0.7"