Apply suggestions from code review

Co-authored-by: Aditya Sharad <6874315+adityasharad@users.noreply.github.com>

Author: aeisenberg

extensions/ql-vscode/CHANGELOG.md

@@ -7,7 +7,7 @@
 - Query results with no string representation will now be displayed with placeholder text in query results. Previously, they were omitted. [#694](https://github.com/github/vscode-codeql/pull/694)
 - Add a label for the language of a database in the databases view. This will only take effect for new databases created with the CodeQL CLI v2.4.1 or later. [#697](https://github.com/github/vscode-codeql/pull/697)
 - Add clearer error message when running a query using a missing or invalid qlpack. [#702](https://github.com/github/vscode-codeql/pull/702)
-- Add clearer error message when trying to run command from the query history view and no item is history selected. [#702](https://github.com/github/vscode-codeql/pull/702)
+- Add clearer error message when trying to run a command from the query history view if no item in the history is selected. [#702](https://github.com/github/vscode-codeql/pull/702)
 
 ## 1.3.7 - 24 November 2020
 

extensions/ql-vscode/package.json

@@ -304,7 +304,7 @@
       },
       {
         "command": "codeQLQueryHistory.openQuery",
-        "title": "Open the Query that Produced these results",
+        "title": "Open the query that produced these results",
         "icon": {
           "light": "media/light/edit.svg",
           "dark": "media/dark/edit.svg"

extensions/ql-vscode/src/run-queries.ts

@@ -479,7 +479,7 @@ export async function compileAndRunQueryAgainstDatabase(
   const packConfig = await cliServer.resolveLibraryPath(diskWorkspaceFolders, queryPath);
 
   if (!packConfig.dbscheme) {
-    throw new Error('No dbscheme. Is your qlpack.yml missing or invalid?');
+    throw new Error('Could not find a database scheme for this query. Please check that you have a valid qlpack.yml file for this query, which refers to a database scheme either in the `dbscheme` field or through one of its dependencies.');
   }
 
   // Check whether the query has an entirely different schema from the