Update discord invite links (#30909)

* Update discord invite links

* Point to Stack Exchange for support

docs/docusaurus.config.js

@@ -100,7 +100,7 @@ module.exports = {
           position: "right",
         },
         {
-          href: "https://discordapp.com/invite/pquxPsq",
+          href: "https://solana.com/discord",
           // label: "Discord",
           className: "header-link-icon header-discord-link",
           "aria-label": "Solana Discord",
@@ -163,7 +163,7 @@ module.exports = {
             },
             {
               label: "Discord »",
-              href: "https://discordapp.com/invite/pquxPsq",
+              href: "https://solana.com/discord",
             },
             {
               label: "Twitter »",

geyser-plugin-interface/README.md

@@ -22,4 +22,4 @@ an external PostgreSQL databases.
 
 More information about Solana is available in the [Solana documentation](https://docs.solana.com/).
 
-Still have questions?  Ask us on [Discord](https://discordapp.com/invite/pquxPsq)
+Still have questions?  Ask us on [Stack Exchange](https://sola.na/sse)

sdk/README.md

@@ -12,4 +12,4 @@ More information about Solana is available in the [Solana documentation](https:/
 
 The [Solana Program Library](https://github.com/solana-labs/solana-program-library) provides examples of how to use this crate.
 
-Still have questions?  Ask us on [Discord](https://discordapp.com/invite/pquxPsq)
+Still have questions?  Ask us on [Stack Exchange](https://sola.na/sse)

sdk/program/README.md

@@ -12,4 +12,4 @@ More information about Solana is available in the [Solana documentation](https:/
 
 [Helloworld](https://github.com/solana-labs/example-helloworld) and the [Solana Program Library](https://github.com/solana-labs/solana-program-library) provide examples of how to use this crate.
 
-Still have questions?  Ask us on [Discord](https://discordapp.com/invite/pquxPsq)
+Still have questions?  Ask us on [Stack Exchange](https://sola.na/sse)