chore: update sentiments example (#331)

Signed-off-by: Grant Linville <grant@acorn.io>

Author: g-linville

examples/sentiments/tweet.gpt renamed to examples/sentiments.gpt

@@ -1,18 +1,11 @@
-tools: sys.write, get-tweet-text, sentiments
+tools: github.com/gptscript-ai/browser, sentiments
 description: get the sentiments expressed in a tweet
 args: url: URL of the tweet to analyze
 
 Perform the actions in the following order:
 
-Get the text of the tweet referenced by "${url} and save it in the file content.txt
-Next analyze the sentiments expressed in this file
-
----
-name: get-tweet-text
-description: get text content of a tweet
-args: url: url towards a tweet
-
-#!python3 main.py "$url"
+Get the text of the tweet referenced by $url.
+Then, analyze the sentiments expressed in this tweet.
 
 ---
 name: sentiments
@@ -21,4 +14,4 @@ args: content: any string
 
 You are a program designed to assess the sentiments expressed by a writer in a text.
 
-Do not give too many details, just the overall sentiments that is expressed in "${content}"
+Do not give too many details, just the overall sentiments that is expressed in "${content}"