Standardise the use of ShellError::UnsupportedInput and ShellError::TypeMismatch and add spans to every instance of the former (#7217)

# Description

* I was dismayed to discover recently that UnsupportedInput and
TypeMismatch are used *extremely* inconsistently across the codebase.
UnsupportedInput is sometimes used for input type-checks (as per the
name!!), but *also* used for argument type-checks. TypeMismatch is also
used for both.
I thus devised the following standard: input type-checking *only* uses
UnsupportedInput, and argument type-checking *only* uses TypeMismatch.
Moreover, to differentiate them, UnsupportedInput now has *two* error
arrows (spans), one pointing at the command and the other at the input
origin, while TypeMismatch only has the one (because the command should
always be nearby)
* In order to apply that standard, a very large number of
UnsupportedInput uses were changed so that the input's span could be
retrieved and delivered to it.
* Additionally, I noticed many places where **errors are not propagated
correctly**: there are lots of `match` sites which take a Value::Error,
then throw it away and replace it with a new Value::Error with
less/misleading information (such as reporting the error as an
"incorrect type"). I believe that the earliest errors are the most
important, and should always be propagated where possible.
* Also, to standardise one broad subset of UnsupportedInput error
messages, who all used slightly different wordings of "expected
`<type>`, got `<type>`", I created OnlySupportsThisInputType as a
variant of it.
* Finally, a bunch of error sites that had "repeated spans" - i.e. where
an error expected two spans, but `call.head` was given for both - were
fixed to use different spans.

# Example
BEFORE
```
〉20b | str starts-with 'a'
Error: nu:🐚:unsupported_input (link)

  × Unsupported input
   ╭─[entry #31:1:1]
 1 │ 20b | str starts-with 'a'
   ·   ┬
   ·   ╰── Input's type is filesize. This command only works with strings.
   ╰────

〉'a' | math cos
Error: nu:🐚:unsupported_input (link)

  × Unsupported input
   ╭─[entry #33:1:1]
 1 │ 'a' | math cos
   · ─┬─
   ·  ╰── Only numerical values are supported, input type: String
   ╰────

〉0x[12] | encode utf8
Error: nu:🐚:unsupported_input (link)

  × Unsupported input
   ╭─[entry #38:1:1]
 1 │ 0x[12] | encode utf8
   ·          ───┬──
   ·             ╰── non-string input
   ╰────
```
AFTER
```
〉20b | str starts-with 'a'
Error: nu:🐚:pipeline_mismatch (link)

  × Pipeline mismatch.
   ╭─[entry #1:1:1]
 1 │ 20b | str starts-with 'a'
   ·   ┬   ───────┬───────
   ·   │          ╰── only string input data is supported
   ·   ╰── input type: filesize
   ╰────

〉'a' | math cos
Error: nu:🐚:pipeline_mismatch (link)

  × Pipeline mismatch.
   ╭─[entry #2:1:1]
 1 │ 'a' | math cos
   · ─┬─   ────┬───
   ·  │        ╰── only numeric input data is supported
   ·  ╰── input type: string
   ╰────

〉0x[12] | encode utf8
Error: nu:🐚:pipeline_mismatch (link)

  × Pipeline mismatch.
   ╭─[entry #3:1:1]
 1 │ 0x[12] | encode utf8
   · ───┬──   ───┬──
   ·    │        ╰── only string input data is supported
   ·    ╰── input type: binary
   ╰────
```

# User-Facing Changes

Various error messages suddenly make more sense (i.e. have two arrows
instead of one).

# Tests + Formatting

Don't forget to add tests that cover your changes.

Make sure you've run and fixed any issues with these commands:

- `cargo fmt --all -- --check` to check standard code formatting (`cargo
fmt --all` applies these changes)
- `cargo clippy --workspace -- -D warnings -D clippy::unwrap_used -A
clippy::needless_collect` to check that you're using the standard code
style
- `cargo test --workspace` to check that all tests pass

# After Submitting

If your PR had any user-facing changes, update [the
documentation](https://github.com/nushell/nushell.github.io) after the
PR is merged, if necessary. This will help us keep the docs up to date.

crates/nu-command/src/network/url/parse.rs

@@ -43,7 +43,7 @@ impl Command for SubCommand {
         call: &Call,
         input: PipelineData,
     ) -> Result<PipelineData, ShellError> {
-        parse(input.into_value(call.head), engine_state)
+        parse(input.into_value(call.head), call.head, engine_state)
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -91,12 +91,13 @@ fn get_url_string(value: &Value, engine_state: &EngineState) -> String {
     value.into_string("", engine_state.get_config())
 }
 
-fn parse(value: Value, engine_state: &EngineState) -> Result<PipelineData, ShellError> {
+fn parse(value: Value, head: Span, engine_state: &EngineState) -> Result<PipelineData, ShellError> {
     let url_string = get_url_string(&value, engine_state);
 
     let result_url = Url::parse(url_string.as_str());
 
-    let head = value.span()?;
+    // This is the span of the original string, not the call head.
+    let span = value.span()?;
 
     match result_url {
         Ok(url) => {
@@ -176,14 +177,18 @@ fn parse(value: Value, engine_state: &EngineState) -> Result<PipelineData, Shell
 
                 _ => Err(ShellError::UnsupportedInput(
                     "String not compatible with url-encoding".to_string(),
+                    "value originates from here".into(),
                     head,
+                    span,
                 )),
             }
         }
         Err(_e) => Err(ShellError::UnsupportedInput(
-            "Incomplete or incorrect url. Expected a full url, e.g., https://www.example.com"
+            "Incomplete or incorrect URL. Expected a full URL, e.g., https://www.example.com"
                 .to_string(),
+            "value originates from here".into(),
             head,
+            span,
         )),
     }
 }