Add TeXpresso extension (#2514)

This is an extension to be used alongside the LaTeX one, providing a
(very new) language server which only deals with live preview of a LaTeX
document using [TeXpresso](https://github.com/let-def/texpresso), while
`texlab` (from other extension) will provide all the other language
server capabilities (go-to-definition, completions, snippets...).
TeXpresso is a very experimental project but pulls off something not
seen anywhere else in the LaTeX world with the preview updating smoothly
with every keystroke. This particular project (LSP and zed integration)
was prompted by a [user request in the LaTeX
extension](rzukic/zed-latex#85) and since then
I have personally found it incredibly compelling.

*Demo showing live preview and inverse-search (clicking on parts of
preview to move cursor in editor:*


https://github.com/user-attachments/assets/e3fd9773-c396-419b-8a12-c3925cdd28a3

Author: lnay

.gitmodules

@@ -1926,6 +1926,10 @@
 	path = extensions/terrible-theme
 	url = https://github.com/nooooaaaaah/terrible-zed.git
 
+[submodule "extensions/texpresso"]
+	path = extensions/texpresso
+	url = https://github.com/lnay/zed-texpresso.git
+
 [submodule "extensions/the-best-theme"]
 	path = extensions/the-best-theme
 	url = https://github.com/Nidal-Bakir/zed-the-best-theme.git

extensions.toml

@@ -1972,6 +1972,10 @@ version = "0.1.3"
 submodule = "extensions/terrible-theme"
 version = "0.0.3"
 
+[texpresso]
+submodule = "extensions/texpresso"
+version = "0.0.1"
+
 [the-best-theme]
 submodule = "extensions/the-best-theme"
 version = "0.0.1"