web-search: update alias for stackoverflow (#7660)

Changed from `stack` because it conflicts with Haskell Tool Stack

Fixes #7659

plugins/web-search/README.md

@@ -37,6 +37,7 @@ Available search contexts are:
 | `ecosia`              | `https://www.ecosia.org/search?q=`       |
 | `goodreads`           | `https://www.goodreads.com/search?q=`    |
 | `qwant`               | `https://www.qwant.com/?q=`              |
+| `stackoverflow`       | `https://stackoverflow.com/search?q=`    |
 
 Also there are aliases for bang-searching DuckDuckGo:
 

plugins/web-search/web-search.plugin.zsh

@@ -52,7 +52,7 @@ alias baidu='web_search baidu'
 alias ecosia='web_search ecosia'
 alias goodreads='web_search goodreads'
 alias qwant='web_search qwant'
-alias stack='web_search stackoverflow'
+alias stackoverflow='web_search stackoverflow'
 
 #add your own !bang searches here
 alias wiki='web_search duckduckgo \!w'