docs(exercises): move template code above, plus move the "where are f…

…unctions from?" to earlier.

Closes #84

sessions/dplyr-joins.qmd

@@ -211,6 +211,24 @@ and extracts the user ID from it. **First step**: While in the
 `doc/learning.qmd` file, convert this code into a function, using the
 same process you've done previously.
 
+Use this code as a guide to help complete the exercise tasks below:
+
+``` {.r filename="doc/learning.qmd"}
+extract_user_id <- ___(___) {
+    ___ <- ___ |>
+        ___mutate(
+            user_id = ___str_extract(file_path_id,
+                                     "user_[0-9][0-9]?"),
+            .before = file_path_id
+        ) |>
+        ___select(-file_path_id)
+    return(___)
+}
+
+# This tests that it works:
+# extract_user_id(user_info_df)
+```
+
 1.  Call the new function `extract_user_id` and add one argument called
     `imported_data`.
     -   Remember to output the code into an object and `return()` it at
@@ -232,32 +250,6 @@ same process you've done previously.
 6.  Add and commit the changes to the Git history with
     {{< var keybind.git >}}.
 
-::: callout-tip
-If you don't know what package a function comes from when you need to
-append the package when using `::`, you can find out what the package is
-by using the help documentation `?functionname` (can also be done by
-pressing F1 when the cursor is over the function). The package name is
-at the very top left corner, surrounded by `{ }`.
-:::
-
-Use this code as a guide to help complete this exercise:
-
-``` {.r filename="doc/learning.qmd"}
-extract_user_id <- ___(___) {
-    ___ <- ___ |>
-        ___mutate(
-            user_id = ___str_extract(file_path_id,
-                                     "user_[0-9][0-9]?"),
-            .before = file_path_id
-        ) |>
-        ___select(-file_path_id)
-    return(___)
-}
-
-# This tests that it works:
-# extract_user_id(user_info_df)
-```
-
 ```{r solution-user-id-extract}
 #| eval: true
 #| output: false

sessions/functions.qmd

@@ -694,6 +694,14 @@ state which package the function is from, R will use the function that
 it finds first - which isn't always the function you meant to use. We
 also do this step at the end of making the function because doing it
 while we create it can be quite tedious.
+
+::: callout-tip
+If you don't know what package a function comes from when you need to
+append the package when using `::`, you can find out what the package is
+by using the help documentation `?functionname` (can also be done by
+pressing F1 when the cursor is over the function). The package name is
+at the very top left corner, surrounded by `{ }`.
+:::
 :::
 
 Alright, let's go into `R/functions.R` and add `readr::` to each of the